FluxLetter

The Newsletter of FLUXNET Vol. 3 No. 1, April, 2010

Carbon dioxide flux measurements at young post-fire Highlight FLUXNET site Boreal forest sites in central Canada Canadian Boreal Forests by Brian Amiro

Fire in the boreal forest lightning, and many large fires are tion following fire, which is a Fire clearly is one of the most difficult to control because of function of the pre-fire vegeta- In This Issue: important processes that control the huge amount of energy re- tion and the post-fire environ- vegetation development in the leased (often > 10 MW/m of fire ment. Much of the area burned circumboreal forest. Figure 1 line; Amiro et al. 2004) and the is characterized by total tree FLUXNET site: graphically demonstrates that the remote location. death, and the young post-fire Canadian Boreal Forests Brian Amiro……...……….....Pages 1-4 wide band of the North Ameri- Fire affects the forest carbon (C) vegetation is dominated by fast can boreal forest has experi- balance through two physical growing successional species, enced much fire in recent dec- events: first, carbon is released which are eventually succeeded Editorial: ades, and this has been typical by combustion during the fire by longer-lived tree species. Vargas R, Baldochhi DD……..Page 5 over the past few thousand event, and second, the post-fire Direct fire combustion releases -2 A plea for a fully open data pol- years. In Canada alone, an aver- forest carbon dynamics are a in Canada are about 1.5 kg C m icy for FLUXNET age of 2 to 3 million hectares combination of carbon net up- on average, plus some additional Han Dolman …….……Page 6 burn annually, although there is take by regenerating vegetation greenhouse gases such as meth- Integrating remote sensing and large inter-annual variability and decomposition of fire-killed ane and nitrous oxide (Amiro et flux measurements (Stocks et al. 2002). About 2/3 vegetation. This is further con- al. 2009). If a forest is to remain John Gamon………….…Pages 7-10 of the area burned is caused by trolled by the type of regenera- carbon-neutral, it needs to gain

FLUXNET young scientist: Lutz Merbold ………...….Pages 11-12

Research: Investigating disturbance and recovery following a hurricane along the Ever- glades mangrove coast Engel V, Fuentes J, Barr J …Pages 13-16

Impacts of beetle-induced forest mortality on carbon, water and nutrient cycling in the Rocky Mountains Pendall E, Ewers B, Norton U, Brooks P, Massman WJ, Barnard H, Reed D, Aston T, Frank J…………..Pages 17-21

A tribute to Laurent Misson …………………….....Pages 22-25

Figure 1: Fires across boreal North America from 1980 to 1999. Each black polygon represents a burned area. The blue line across Canada represents the approximate southern limit of boreal forest. The northern limit corresponds to the area north of the fire polygons. The fire poly- gons were kindly provided by Canadian fire agencies (provinces, territories, national parks) and the State of Alaska. Page 2

Canadian Boreal Forests

Figure 2: Photographs of the post-fire sites. The upper panels show the 1998 site at 7 years of age, the bottom left panel is the 1989 site and the bottom right is the 1977 site.

this combusted carbon back Forest Service (led by Brian post-fire sites had ages that had been selected to represent over the period between se- Amiro) also established a post- were typical of major fire years large areas of single tree spe- quential fires. Inventory models fire chronosequence in central in this region. Although we had cies, which became the South- tell us that fires are an important Saskatchewan. The Manitoba earlier field campaign measure- ern Old Aspen, the Southern control determining whether the and Saskatchewan sites took ments (Amiro 2001), the first Old Jack Pine, and Southern boreal forest is a net carbon advantage of the long-term ma- full year of measurement was in Old Black Spruce sites. Much source or sink over any given ture forest anchor sites that 2001. We gathered full annual of the surrounding forest tends period (Kurz et al. 2008). continued since BOREAS. We data from 2001 to 2006 at the to be a mixture of these species selected sites that had been 1998 site, 2003 to 2005 at the (often with patches that vary on The post-fire sites in central burned in 1998, 1989 and 1977 1989 site, and 2004 to 2006 at the order of a few 100 metres), Saskatchewan that were within the former the 1977 site (Amiro et al. so it is difficult to identify a true In the late 1990s, following the southern study area of BOREAS 2006a, Mkhabela et al. 2009). mature “control” site for the BOREAS experiments in Canada, (Figure 2). This area is now the In this area, post-fire vegetation post-fire chronosequence. We eddy covariance towers were Boreal Ecosystem Research and development is often a compe- really need to understand the established along post-fire Monitoring Sites (BERMS), sup- tition between fast growing way that these species compete chronosequences in northern ported by Environment Canada, trembling aspen and slower and colonize the landscape to Manitoba and Alaska (led by the Canadian Forest Service, growing jack pine and black determine the carbon flux dy- Mike Goulden and Jim Rander- Parks Canada, and funded by spruce. We had all three spe- namics. son, respectively, University of various agencies to support cies at the post-fire sites. How- The post-fire sites illustrate that California, Irvine). The Canadian university investigators. The ever, the mature BOREAS sites fire changes the energy balance, Page 3

Canadian Boreal Forests

red gas analysers. We identi- fied problems with measure- ments during winter, because we often saw carbon uptake during frozen conditions. The issue has been identified as sensor heating, but there is no easy correction for our data because the tilted configuration makes it difficult to derive heat transfer equations. Our interim solution has been to exclude all carbon flux data when air tem- peratures are below 0 °C, and gap-fill these by extending re- gressions from higher tempera- tures (i.e., only respiration is gap filled). This adds to the uncertainty in the data, although in some years, we have done a sensitivity analysis using various winter respiration rates to see the effect (Amiro et al. 2006a).

Figure 3. Net ecosystem production at the fire chronosequence sites. Positive NEP is a forest carbon sink. The mature site is the southern old Comparisons with nearby jack pine site as a reference. harvested sites with younger sites having higher at five years of age. However, years could be just a short The BERMS area also has a albedo over about the first 20 the last two points in the time period when the coarse debris harvest chronosequence, which years (Amiro et al. 2006b). Peak series for the 1998 site (ages 7 quickly decomposes. This has allowed a comparison of evapotranspiration is suppressed and 8) appear to be a slight car- would be consistent with ob- fire and harvest carbon dynam- immediately following the fire, bon source again. This is caused servations when walking ics (Mkhabela et al. 2009). but quickly becomes greater by heterotrophic respiration through forests of different Despite the very close prox- than mature forests because of increasing faster than gross eco- ages: sites less than 20 years imity of all sites (less than 100 more broad-leaved species system production (GEP), possi- often have perched deadfall, km), site differences, such as dominating the regenerating bly because of more fire- whereas those older than 30 soil moisture, make it difficult forest. Summer-time daily mean generated coarse woody debris years are often easily traversed to attribute different carbon Bowen ratios can be as low as becoming in contact with the because fire-killed trees are dynamics caused by fire com- 0.5 at about 10 years, compared ground and decomposing. The lying on the ground and mostly pared to harvesting. However, to mature coniferous forests 1989 site shows strong net car- decayed. The mature old jack the post-fire sites definitely with values of about 2. bon uptake. The 1977 site is a pine site is a slight carbon sink have a greater amplitude in The net ecosystem production consistent carbon source. Al- in most years. As mentioned, both GEP and ecosystem respi- (NEP) data tell an interesting though this site has slightly more this is not the perfect control ration, which is clearly shown story. Figure 3 shows annual GEP than the 1989 site, it has site for the post-fire chronose- by a greater response of GEP NEP for the three post-fire sites greater respiration, probably quence, which will likely de- to photosynthetically-active plus the southern old jack pine caused by decomposition of velop into an aspen/pine/spruce radiation and respiration to site. The youngest site (burned coarse woody debris that is mixture of patches. temperature. This is caused by in 1998) shows clearly increasing visibly soft and punky. This pe- As a side note, the three post- more diverse successional vege- NEP, reaching carbon neutrality riod of carbon loss at about 30 fire sites used open-path infra- tation at the post-fire sites, possibly because of heavier soils Page 4

Canadian Boreal Forests

and a more diverse vegetation Mkhabela. Alberto Orchansky, References history. Rick Hurdle, Dave Wieder, Jeff Amiro, B.D. 2001. Paired-tower Weir, Zoran Nesic and a several measurements of carbon and energy The Future summer students provided tech- fluxes following disturbance in the boreal forest. Global Change Biol. 7, The Saskatchewan post-fire nical support. We thank Harry 253-268. chronosequence measurements McCaughey for providing the Amiro, B.D., Logan, K.A., Wotton, ended in 2006. However, we data from the old jack pine site, B.M., Flannigan, M.D., Todd, J.B., are recognizing that there is as well as the BERMS manage- Stocks, B.J., D.L. Martell. 2004. Fire weather index system components of much more to be learned by ment team and the BERMS scien- large fires in the Canadian boreal forest. Inter. J. Wildland Fire 13, 391- measurements at such sites, tific committee, especially Andy 400. especially related to the dynam- Black and Alan Barr. Kim Logan Amiro, B.D., Barr, A.G., Black, T.A., ics between successional vegeta- (Canadian Forest Service) pro- Iwashita, H., Kljun, N., McCaughey, tion development and decompo- duced the fire map shown in J.H., Morgenstern, K., Murayama, S., Nesic, Z., Orchansky, A.L., Saigusa, N. sition of the dead biomass cre- Figure 1. 2006a. Carbon, energy and water ated by fire. Projections indicate fluxes at mature and disturbed forest sites, Saskatchewan, Canada. Agric. that it is likely we will have more contact: For. Meteorol. 136, 237-251. future fire in the boreal forest as Brian Amiro Amiro, B.D., Orchansky, A.L., Barr, a consequence of a warming [email protected] A.G., Black, T.A., Chambers, S.D., climate (Flannigan et al. 2005), Chapin III, F.S., Goulden, M.L., Litvak, M., Liu, H.P., McCaughey, J.H., highlighting the need to under- Department of Soil Science, University McMillan, A., Randerson, J.T. 2006b. stand how these post-fire forests of Manitoba, Winnipeg, Canada The effect of post-fire stand age on the boreal forest energy balance. Agric. operate. These sites, grouped For. Meteorol. 140, 41-50. with data from other disturbance Amiro, B.D., Cantin, A., Flannigan, chronosequences are part of a M.D., de Groot, W.J. 2009. Future current synthesis of data for the emissions from Canadian boreal forest fires. Can. J. For. Res. 39, 383-395. North American Carbon Pro- gram. Flannigan, M.D., Logan, K.A., Amiro, B.D., Skinner, W.R., Stocks, B.J. 2005. Future area burned in Canada. Clim. Acknowledgments Change 72, 1-16.

Funding for these sites came Kurz, W.A., Stinson, G., Rampley, G.J., from diverse sources, notably Dymond, C.C., Neilson, E.T. 2008. Risk of natural disturbances makes the Canadian Forest Service future contribution of Canada's forest (including the Program on En- to the global carbon cycle highly uncertain. Proc. Nat. Acad. Sci. 105, ergy Research and Development, 1551-1555. Action Plan 2000), Environment Mkhabela, M.S., Amiro, B.D., Barr, Canada, Parks Canada, the Flux- A.G., Black, T.A., Hawthorne, I., Kid- net-Canada Research Network ston, J., McCaughey, J.H., Orchansky, A.L., Nesic, Z., Sass, A., Shashkov, A., (NSERC, the Canadian Founda- Zha, T. 2009. Comparison of carbon dynamics and water use efficiency tion for Climate and Atmos- following fire and harvesting in Cana- pheric Sciences, BIOCAP Can- dian boreal forests. Agric. For. Meteo- rol. 149, 783-794. ada; Hank Margolis as Principal Investigator), and the Canadian Stocks, B.J., Mason, J.A., Todd, J.B., Bosch, E.M., Wotton, B.M., Amiro, Carbon Program (Canadian B.D., Flannigan, M.D., Hirsch, K.G., Foundation for Climate and Logan, K.A., Martell, D.L., Skinner, W.R. 2002. Large forest fires in Can- Atmospheric Sciences). Re- ada, 1959-1997. J. Geophys. Res. 107, search at the fire sites was con- 8149, doi: 10.1029/2001JD000484. ducted by graduate students/ postdoctoral fellows Alison Sass, Sarabpreet Singh, and Manasah Page 5

Editorial Rodrigo Vargas and Dennis Baldocchi

We are delighted to celebrate the implications of data sharing how ecosystem processes are with the FLUXNET community for the broader scientific com- modified by disturbances. the starting of the third year of munity. Furthermore, John Ga- Our excitement about this issue FluxLetter. Without the contri- mon discusses the importance of is shadowed by the lost of a bution of FLUXNET scientists integrating flux measurements colleague and friend: Laurent from different regional networks with remote sensing measure- Misson. With this issue we want and active participation of Young ments. He presents SpecNet as a to make a small tribute to Scientists the success of FluxLet- way to bridge the measurement Laurent and share with the com- ter would not be the gap between satellites and flux munity thoughts from close same. FluxLetter is proud to towers. We encourage the friends and colleagues. The highlight the high quality of ob- FLUXNET community to use FLUXNET Office is deeply servations of the “breathing of FluxLetter as a way to share touched by the lost of Laurent the biosphere” that scientists are ideas and opinions throughout and we invite the community to recording all around the globe. the network. read and post on the FLUXNET These unprecedented measure- FluxLetter has tried to present blog at: http://www.fluxdata.org/ Blog/default.aspx ments are part of the legacy that the diversity of opinions, re- FLUXNET is contributing for the search sites, young members, broader scientific community. and research around FLUXNET. With this incredible wealth of This issue highlights the effects information new discussions are of disturbances in ecosystems arising about the use of the data showing three cases (fire, hurri- set. In this number, Han Dolman cane, and insects). Thus, this (Chairman of the Terrestrial shows that importance of using Observation Panel for Climate) long term eddy flux measure- discusses about data policy and ments to bring new insights on Page 6

A plea for a fully open data policy for FLUXNET Han Dolman

It has been now over more than see it, because the next genera- Kyoto type assessments, to often on a shoestring budget. 10 years since FLUXNET started tion of whizz kids from other weather prediction and climate Instead we can then develop and expanding rapidly. The recent institutions and next-door de- models. As a response to this, in test our novel techniques at debate about the leaked CRU partments has no access to our several continents groups are in these routine sites and do our emails urges us to reconsider data. the process of moving this re- analysis work on the full set of once again our data policies. In FLUXNET has shown great value search driven network into a sites. essence the debate about these because of the number of sites more sustainable routine moni- I strongly believe that we can be emails centers around the use of and biomes that are involved, toring network. It is vital for in the driver seat for a number data and, in particular, whether and the common data processing achieving this sustainability that of the processes mentioned in such data is freely and publicly and analysis techniques that our data policy is more open. this comment, such as producing available. This goes from the were developed within our com- Such a policy is completely in exiting new science and develop processed data that tends to be munity. The la Thuile dataset line with recommendation of the the routine monitoring net- more publicly available, to the shows this progress and the Global Climate Observing Sys- works. There are also major raw data where data quality added value that has been made tem (GCOS) and the Group on unknowns in the role of the control and assessment may in harmonized data processing Earth Observation’s (GEO) terrestrial vegetation in the car- generate debates between re- and common analysis tools. The guidelines and data principles (1). bon cycle or in the climate sys- search groups. While the recent la Thuile set and previous syn- For the establishment of, for tem that we yet need to address initiative to open up part of the thesis datasets have also gener- instance a Global Integrated with our techniques. The re- la Thuile database is indeed a ated numerous co-authorships Carbon Observing System, we sponse of vegetation to drought, much needed and fully laudable for most of us, which have sig- need to make the transition the interaction of carbon with first step, I would like to argue nificantly helped shaping our from research network to rou- water and nitrogen, the role of that we learn more from the careers. Both data takers and tine monitoring network (2). forest in a changing climate, or CRU debate and that all data we modelers have benefited from This cannot be achieved without how can carbon sequestration take in FLUXNET is made pub- these common analyses and an open data policy and trans- offset effects on the hydrological licly available. while the cases where data tak- parency. It is in our own and balance of forests or change Progress in science is often best ers have not been properly ac- societies best interest that the radiative properties? All of these served by applying new analysis knowledged or data been mis- data of our current network is questions are of vital importance techniques and methods to “old” used were painful and should as freely available as possible, for progress in the broad field of data. The young aspiring climate have been avoided, they are since that only increases the climate or Earth System Science. modeler for instance, who is negligible in number compared chances of making this transition. We can loose this valuable op- developing a complicated land to the overwhelmingly large An open data policy on its own portunity to play a leading role surface scheme, would love to number of successful collabora- is not sufficient to make this and develop into a closed, in- have FLUXNET data on surface tion. transition. Data quality control ward looking community. I do energy partitioning. For most of Our FLUXNET network is how- and assessment need to be an not believe we are a closed com- us, particularly the more ecologi- ever still run by a rather loose integral part of an open data munity, but to be able to lead cally minded, surface energy group of individual institutions, policy. Particularly with the la the field I suggested above, we partitioning is a nice side product that follow not always the same Thuile harmonized data sets we urgently need to open up our to see if our eddy covariance protocols, exert not always the have taken major strides to- datasets more widely. achieves energy balance closure. same quality control on the data wards such a transparent quality In the hands of this climate mod- and often suffer from periodic control procedure. Once such contact: eler such data however are at shortfalls in funding leading to routine systems exist, we can Han Dolman the core of his validation efforts. the use of old equipment or use the data reliably and make [email protected] Still, our current restricted data substantial data loss. The data progress in our understanding of policy does not allow such ex- FLUXNET produces is however the working of the major bio- Long time member-contributor to change easily. There may well be increasingly recognized as an geochemical cycles on land. This FLUXNET increased understanding lurking extremely rich and essential data stops us having to bear the full around the corner, but we fail to source in various fields, from burden of running these sites, VU University Amsterdam Page 7

Integrating remote sensing and flux measurements John A. Gamon

Eddy covariance is widely used flux estimates that better agree ing the integration of optical dinated optical sampling ap- to quantify biospheric- with ground-measured fluxes sampling with flux measurements proach are briefly outlined, with atmospheric carbon and water (Rahman et al. 2005, Gamon et for the purpose of improving the goal of spurring greater vapor fluxes and to improve our al. 2006b, Sims et al. 2006b). A remote estimates of carbon and adoption of this method at understanding of the controls on greater agreement among flux water vapor exchanges (Gamon FLUXNET sites, and a wider these fluxes. However, from a estimates from these diverse et al. 2006b, 2010). Integrated collaboration between the re- global perspective, flux towers sampling methods is becoming optical and flux sampling has mote sensing and flux sampling represent “points” on the increasingly crucial as policymak- been adopted at a number of communities. ground and cannot cover the ers and carbon markets demand flux tower sites, and has been A wide range of optical sampling entire range of climate space defensible and transparent data embraced by several projects methods have been developed to (Running et al. 1999). Further- on biospheric carbon exchange. within the European Union (e.g. assess biosphere-atmosphere more, eddy covariance is best One way to bridge the measure- COST Action ESO903 – fluxes. Optical measurements applied in flat terrain and uni- ment gap between satellites and “Spectral Sampling Tools for can serve as useful proxies for form vegetation, leaving much of flux towers is to apply scale- Vegetation Biophysical Parame- variables in flux models. The the world’s terrestrial surface appropriate optical sampling that ters and Flux Measurements in light-use efficiency model states unsampled. Satellite remote more closely matches the tem- Europe”), but the full advantages that GEP can be derived as the sensing, including the MODIS poral and spatial scale of the flux of this integration across the product of absorbed PAR sensor, now offers more com- tower footprint. SpecNet FLUXNET and SpecNet commu- (APAR) and the efficiency (ε, also plete and uniform global cover- (Spectral Network) was formed nities have yet to be widely real- called light-use efficiency or LUE) age and calculates carbon fluxes with this goal in mind. Since ized. In this editorial, the chal- with which absorbed PAR is based on the light-use efficiency 2003, SpecNet has been advocat- lenges and benefits of this coor- converted to fixed carbon model (Running et al. 2004). Relative to field sampling, MODIS operates at coarse tem- poral and spatial scales, creating data incongruities when compar- ing satellite data to flux tower data. Efforts at direct compari- son often reveal discrepancies between remotely sensed and ground measurements. Sources of disagreement include the difference in sampling scales; b) the reliance of satellite algo- rithms on biome-based lookup tables and interpolated meteoro- logical data fields to calculate final flux products; and c) the inability of current algorithms to adequately capture short-term variability due to disturbance and stress (Cheng et al. 2006, Run- ning 2008). A more direct as- sessment of surface-atmosphere fluxes from remote sensing could lead to improved carbon Figure 1 - “Phenology station” sampling NDVI in a fen site, Churchill, Manitoba, Canada. Note the flux tower in the background (operated by M. Tenuta, University of Manitoba). Page 8

Integrating remote sensing and flux measurements

tosynthetic light-use efficiency, pheric scattering effects are and vegetation water or pigment considered (Drolet et al. 2008, content. Due to their broad and Hilker et al. 2009). detailed spectral coverage, these Finally, a new variety of imaging sensors provide more options spectrometers (Ustin et al. for modeling carbon or water 2004, Bannon 2009), combining vapor fluxes than simple radi- the power of imagery with spec- ometers. Recent advances in tral information, are becoming a sensor design and application, cost-effective solution to the including robotic and multi-angle problem of mapping within a sampling methods (figures 3-5), satellite pixel. These spec- now allow automated field sam- trometers can be mounted on pling of flux tower footprints towers, trams, or airborne plat- (Gamon et al. 2006a, Leuning et forms to provide a range of al. 2006, Hilker et al. 2007). coverage in the region of a flux These automated instruments tower, and are particularly use- Figure 2 - PRI Sensors mounted in a Douglas-fir forest canopy, Campbell River, British Co- lumbia, Canada. Sensors based on a design by Garrity et al. 2010. Photo courtesy Martin provide novel methods for relat- ful in footprint analyses (Sims et van Leeuwen. ing whole-ecosystem optical al. 2006a). When mounted on (Monteith 1977). Good meth- tower sites. When properly properties to flux measurements airborne platforms, these spec- ods exist for measuring both applied, these instruments can and enable year-round observa- trometers provide a bridge terms of this model using optical provide a surrogate normalized tion of light-use efficiency from between field sensors and satel- sensors: APAR can be measured difference vegetation index optical sensors (Sims et al. lite sensors (Cheng et al. 2006). with PAR or NDVI sensors, and (NDVI), a useful metric of both 2006a, Hall et al. 2008, Hilker et In combination, automated field light-use efficiency can be meas- absorbed PAR and phenology that al. 2008, Middleton et al. 2009). optical sensors, aircraft imaging ured with PRI (the Photochemi- often scales closely with whole- Recent studies have demon- spectrometers, and satellite cal Reflectance Index, Gamon et ecosystem carbon fluxes strated these stand-level signals measurements provide a power- al. 1997, 2001, Garrity et al. (Huemmrich et al. 1999) or bio- can be related to MODIS signals ful array of data sources for 2010). Similarly, optical sensors mass gain (Gamon et al. 2010). when directional and atmos- modeling surface-atmosphere can estimate vegetation water Similarly, many sites are now content which provides an indi- employing webcams for surrogate cator of stress for drought- NDVI measurements (Richardson prone ecosystems. Water con- et al. 2007, see also figure 5). tent can be used to estimate Two-band radiometers are also evapotranspiration (Claudio et being used for other wavebands al. 2006, Fuentes et al. 2006), and indices, including the photo- and can provide further indica- chemical reflectance index (PRI), tions of light-use efficiency. offering year-round estimates of Optical sampling methods exist photosynthetic light-use efficiency at several levels of technology (Garrity et al. 2010, figure 2). and cost (figures 1-5). At the An intermediate level of technol- most basic level, 2-band ogy and cost is provided by field “radiometers” can be assembled spectrometers, including from paired upward- and down- “hyperspectral” (narrowband) ward-looking PAR sensors and sensors that can provide any num- pyranometers, and these sensors ber of proxy measures, including Figure 3 – Tram system (Gamon et al. 2006a) sampling spectral reflectance of the flux tower are already present at many flux absorbed radiation (APAR), pho- footprint in a prairie grassland, Lethbridge, Alberta, Canada. Note the flux tower (operated by L. Flanagan, U. Lethbridge) at the end of tramline. Page 9

Integrating remote sensing and flux measurements

challenges (Gamon 2006b, 2010), site registration tool that gathers analogous to some of the data and makes available basic infor- standardization and sharing ef- mation on sites and optical sam- forts initiated within the flux pling methods, and we invite community (Agarwal et al. 2008, members of the flux sampling 2010). community employing optical To fully benefit from the power sampling to register online. of remote sensing, optical sam- Members of the FLUXNET and pling and flux measurements, a SpecNet communities are begin- greater level of coordination ning to explore more effective between the flux, optical sam- methods for sharing and inte- pling, and remote sensing com- grating data. Better integration munities will be needed, with a of flux and optical sampling can concerted focus on informatics, ultimately yield an improved including issues of data prove- understanding of the spatial and

Figure 4 - AMSPEC system (Hilker et al. 2007) for automated, multi-angle hyperspectral nance and transparency. Full temporal patterns of fluxes, the measurements of a Douglas-fir forest, Campbell River, British Columbia, Canada. realization of the synergistic controls of these fluxes, and the opportunities provided by linking opportunities for biospheric fluxes across multiple spatial and prevent effective integration of flux and optical sampling will carbon sequestration. temporal scales. Flux models optical and flux measurements. require that a larger percentage driven from optical sensors pro- Primary among them is the cur- of flux tower sites gather and Acknowledgements: Thanks to D. vide independent estimates of rent lack of standardization report optical sampling data Agarwal, N. Coops, T. Hilker, S. biosphere-atmosphere fluxes that among optical sensors and sam- along with suitable metadata. Running, and D. Thayer and to can be validated against direct pling methods. Different sensor Better cyberinfrastructural ap- members of the SpecNet and flux measurements. By calibrating brands have different spectral, proaches to storing and access- FLUXNET communities for optically-based flux models radiometric and angular re- ing data and metadata are helpful comments and contribu- against direct eddy covariance sponses, and the different tem- needed. The SpecNet web site tions to this editorial. measurements, it is possible to poral and spatial scales of optical (http://specnet.info) provides a extrapolate flux measurements to sampling often make it difficult to larger regions (Rahman et al. directly compare measurements 2001, Fuentes et al. 2006). This across sites. While standardiza- approach provides a “bottom-up” tion can be beneficial, enforce- method of modeling fluxes that ment of standards is difficult and complements “top-down” meth- sometimes stifles innovation. ods of satellite remote sensing One solution lies in creating (Running et al. 2004, Rahman et better informatics and cyberin- al. 2005, Sims et al. 2006b). This frastructure tools (i.e. more integrated, multi-scale analysis of effective databases and meta- optical and flux sensors can help data) that enable the flux and identify areas where satellite optical sampling communities to algorithms need further improve- better define and report the ment, provide a powerful tool for particular sampling methods footprint analyses, or lead to used. To this end, members of additional methods of gap-filling the SpecNet community have missing flux data. begun exploring informatics Figure 5 - AMSPEC II system combining a webcam with multi-angle spectral reflectance measurements of the Southern Old Aspen site, Saskatchewan, Canada. Photo: Thomas A number of challenges currently solutions to data and metadata Hilker. Page 10

Integrating remote sensing and flux measurements

Hilker, T., Lyapustin, A., Hall, F.G., contact: Running, S.W., Baldocchi, D.D., Turner, Gamon, J.A., Cheng, Y., Claudio, H., Wang, Y., Coops, N.C., Drolet, G., & D.P., Gower, S.T., Bakwin, P.S., Hibbard, John A. Gamon MacKinney, L., Sims, D. 2006a. A Black, T.A. (2009). An assessment of K.A. 1999. A global terrestrial moni- photosynthetic light use efficiency from [email protected] mobile tram system for systematic toring network integrating tower fluxes, sampling ecosystem optical properties. space: Modeling the atmospheric and flask sampling, ecosystem modeling and Remote Sensing of Environment. 103, directional impacts on PRI reflectance. EOS satellite Data. Remote Sensing of 246-254 Remote Sensing of Environment, 113, Environment. 70, 108-127. Departments of Earth & Atmospheric 2463-2475 Sciences and Biological Sciences Gamon, J.A., Coburn, C., Flanagan, L., Sims, D.A., Luo, H., Hastings, S., Oechel, Huemmrich, K.F., Kiddle, C., Sanchez- Huemmrich, K. F., Black, T. A., Jarvis, P. W.C., Rahman, A.F., Gamon, J.A. University of Alberta Azofeifa, G.A., Thayer, D., Vescovo, L., G., McCaughy, J. H., Hall, F. G. 1999. 2006a. Parallel adjustments in vegeta- High temporal resolution NDVI phenol- Gianelle, D., Sims, D., Rahman, A.F., tion greenness and ecosystem CO2 Pastorello, G.Z. 2010. SpecNet revis- ogy from micrometeorological radiation exchange in response to drought in a ited: bridging flux and remote sensing sensors. Journal of Geophysical Re- Southern California chaparral ecosys- communities. Canadian Journal of search. 104 No. D22, 27,935-27,944. tem. Remote Sensing of Environment.

Remote Sensing. Accepted. 103, 289-303. Leuning, R., Hughes D., Daniel, P., References Gamon, J.A., Field, C.B., Fredeen, A.L., Coops, N.C., Newnham, G. 2006. A Sims, D.A., Rahman, A.F., Cordova, Thayer, S. 2001. Assessing photosyn- multi-angle spectrometer for automatic Agarwal, D.A. 2008. Fluxnet Synthesis V.D., El-Masri, B.Z., Baldocchi, D.D., thetic downregulation in sunflower measurement of plant canopy reflec- Dataset Collaboration Infrastructure . Flanagan, L.B., Goldstein, A.H., Hollin- stands with an optically-based model. tance spectra. Remote Sensing of FluxLetter, Vol 1, Issue 1, 2008, pp. 5-7. ger, D.Y., Misson, L., Monson, R.K., Photosynthesis Research. 67, 113-125. Environment. 103, 236–245. LBNL Paper LBNL 1273E. http:// Oechel, W.C., Schmid, H.P., Wofsy, escholarship.org/uc/item/3dn028qn S.C., Xu, L. 2006b. On the use of Gamon, J.A., Rahman, A.F., Dungan, J.L., Middleton, E.M., Cheng, Y.B., Hilker, T., MODIS EVI to assess gross primary Schildhauer, M., Huemmrich, K.F. Black, T.A., Krishnan, P., Coops, N.C., Agarwal, D.A. 2010. A data-centered productivity of North American ecosys- 2006b. Spectral Network (SpecNet): and Huemmrich, K.F. 2009. Linking collaboration portal to support global tems, Journal of Geophysical Research. what is it and why do we need it? foliage spectral responses to canopy- carbon-flux analysis. Lawrence Berkeley 111, G04015, Remote Sensing of Environment. 103, level ecosystem photosynthetic light-use National Laboratory: Lawrence Berke- doi:10.1029/2006JG000162. 227-235. efficiency at a Douglas-fir forest in ley National Laboratory. LBNL Paper Canada. Can. J. Remote Sensing. LBNL-1827E. http:// Ustin, S.L., Roberts, D.A., Gamon, J.A., Gamon, J.A., Serrano, L., Surfus, J.S. 35(22), 166-188. www.escholarship.org/uc/ Asner, G.P., Green, R.O. 2004. Using 1997. The photochemical reflectance item/5rm4c0n2 imaging spectroscopy to study ecosys- index: an optical indicator of photosyn- Monteith, J.L. 1977. Climate and the tem processes and properties. BioSci- thetic radiation-use efficiency across efficiency of crop production in Britain. Bannon, D. 2009. Cubes and Slices. ence. 54(6), 523-533 species, functional types, and nutrient Philosophical Transactions of the Royal Nature Photonics 3, 627-629. levels. Oecologia. 112, 492-501. Society of London. B281, 277-294.

Cheng, Y., Gamon J.A., Fuentes, D.A., Garrity, S.R., Vierling, L.A., Bickford. K. Rahman, A.F., Gamon, J.A., Fuentes, Mao, Z.., Sims, D.A., Qiu H-L., Claudio, 2010. A simple filtered photodiode D.A., Roberts, D.A., Prentiss, D. 2001. H.C., Yang, W., and Huete, A. 2006. A instrument for continuous measure- Modeling spatially distributed ecosystem multi-scale analysis of dynamic optical ment of narrowband NDVI and PRI flux of boreal forests using hyperspec- signals in a Southern California chapar- over vegetated canopies. Agriculture tral indices from AVIRIS imagery. Jour- ral ecosystem: a comparison of field, and Forest Meteorology. 150(3), 489- nal of Geophysical Research. 106, No. AVIRIS and MODIS data. Remote 496. D24, 33579-33591. Sensing of Environment. 103, 369-378. doi:10.1016/j.agrformet.2010.01.004.

Rahman, A.F., Sims,D.A., Cordova,V.D. Claudio, H.C., Gamon, J.A., Cheng, Y., Hall, F.G., Hilker, T., Coops, N.C., El-Masri, B.Z. 2005. Potential of Fuentes, D., Rahman, A.F., Qiu, H.-L., Lyapustin, A., Huemmrich, K.F., Middle- MODIS EVI and surface temperature for Sims, D.A., Luo, H., Oechel, W.C. ton, E.M., Margolis, H.A., and Drolet, directly estimating per-pixel ecosystem 2006. Monitoring drought effects on G.G. 2008. Multi-angle remote sensing C fluxes. Geophysical Research Letters. vegetation water content and fluxes in of forest light use efficiency by observ- 32, L19404, chaparral with the 970nm water band ing PRI variation with canopy shadow doi:10.1029/2005GL024127. index. Remote Sensing of Environment. fraction. Remote Sensing of Environment, 103, 304-311. 112(7), 3201-3211. Richardson, A.D., Jenkins, J.P., Braswell,

B.H., Hollinger, D.Y., Ollinger, S.V., Drolet, G.G., Middleton, E.M., Hilker, T., Coops, N.C., Hall, F.G., Smith, M.L. 2007. Use of digital web- Huemmrich, K.F., Hall, F.G., Amiro, Black, T.A., Wulder, M.A., Nesic, Z., & cam images to track spring green-up in B.D., Barr, A.G., Black, T.A., Krishnan, P. (2008). Separating physio- a deciduous broadleaf forest. Oecologia. McCaughey, J.H., & Margolis, H.A. logically and directionally induced 152, 323–334. (2008). Regional mapping of gross light- changes in PRI using BRDF models. use efficiency using MODIS spectral Remote Sensing of Environment, 112, Running, S.W. 2008. Ecosystem distur- indices. Remote Sensing of Environ- 2777-2788 bance, carbon and climate. Science. ment, 112, 3064-3078 321, 652-653.

Hilker, T., Coops, N.C., Nesic, Z., Fuentes, D., Gamon, J.A., Cheng, Y., Wulder, M.A., Black, A.T. 2007. Instru- Running, S.W., Nemani, R.R., Heinsch, Qiu, H.-L., Mao, Z., Sims, D.A., Rahman, mentation and approach for unattended F.A., Zhao, M., Reeves, M., Hashimoto, A.F., Oechel, W.C., Luo, H. 2006. year round tower based measurements H. 2004. A continuous satellite-derived Mapping carbon and water flux in a of spectral reflectance. Computers and measure of global primary production. chaparral ecosystem using vegetation Electronics in Agriculture. 56, 72−84. BioScience. 54(6), 547-560. indices derived from AVIRIS. Remote

Sensing of Environment. 103, 312-323. Page 11

Highlight Young Scientist Lutz Merbold

My name is Lutz Merbold and I fore moved to Jena, a small may change after drainage as one (primarily carbon) in terrestrial am currently working on total town in the east of Germany possible outcome of ongoing ecosystems through the applica- greenhouse gas balances of man- where Ernst Haeckel historically global climate change in the tion of a whole range of different aged grasslands in Switzerland. defined the subtopic of region (Merbold et al. 2009a). In technologies, such as eddy co- The dynamic team I am part of is “ecology” in biology in 1866. particular, the Arctic regions are variance and chamber measure- the Grassland Science Group at Today that same institute of supposedly severely struck by ment. I was offered a PhD posi- the Swiss Federal Institute of ecology continues to do re- increasing global surface tem- tion supervised by Dr. Werner Technology (ETH), Zurich, search on a wide spectrum of peratures. Detailed understand- L. Kutsch at the MPI-BGC and headed by Prof. Nina Buchman. ecological subjects. During my ing of ecosystem responses to was able to spend three years Looking back in the past I tried undergraduate studies I started changing abiotic factors is of working in Zambia and South to remember how I ended up working as a research technician crucial importance in this region Africa. During this time, I special- here: an exciting job which is for the Max- Planck Institute for as this may affect the vast reser- ised in developing a detailed often challenging and at the same Biogeochemistry (MPI-BGC) in voir of carbon stored in perma- understanding of the two major time satisfying, while being able Siberia and returned one year frost soils which were accumu- processes, respiration and pho- to do ecological research around later to an outstanding place lated during the Pleistocene tosynthesis, in the still poorly the globe and interact with dif- (Figure 2) to do my MSc thesis (Dutta et al. 2006; Zimov et al. understood miombo woodlands ferent cultures and people. After research. 2006). The study showed strong (see also Fluxletter Vol.2 No. 1, finishing my undergraduate stud- In Siberia I tried to explore how decreases in the global warming 2009). ies in biology I wanted to focus the ecosystem carbon exchange potential of the tundra ecosys- One part of the thesis was to primarily on ecology and there- of a typical tundra ecosystem tem after drainage, while simulta- study the variation of ecosystem neously functioning as a small carbon fluxes across a rainfall source of greenhouse gases to gradient in a variety of ecosys- the atmosphere. The data col- tems across Africa (Merbold et lected can be used a baseline for al. 2009b). The study showed long-term ecological research at that mean annual precipitation is this experimental site. the major driver of carbon fixa- Doing research in Siberia influ- tion in savanna ecosystems, enced my further decision on while ecosystem type showed strengthening my scientific com- less influence. Temperature had prehension of nutrient cycling an effect on ecosystem respira-

Figure 2: Aerial image of a large scale drainage experiment in a common Figure 1: Lutz Merbold tussock-tundra ecosystem, Far-East Federal District, Russia. Photo credit S.A. Zimov Page 12

Highlight Young Scientist

pogenic disturbance. Anthropo- horizon to more complex struc- genic disturbances were defined tures in nutrient cycling. This will on two different timescales, long include the linkage of other nu- -term such as climate change in trient cycles (e.g. Nitrogen and Siberia and short-term such as Phosphorous) and determining deforestation and continuous total greenhouse gas balances of land degradation due to charcoal ecosystems as well as associated production in the miombo wood- new techniques to study the land in Zambia. various pathways of C and N in the terrestrial biosphere. One of Understanding the responses of my additional interests is to ecosystems to disturbances such learn more about large scale as forest degradation by logging, ecological models. charcoal production and global climate change in the future will contact: be one of the big challenges not Lutz Merbold only in terms of carbon storage [email protected] but also in the context of con- serving biodiversity. In trying to comprehend such responses, I Further Reading combined carbon flux measure- Merbold L, Ardö J, Arneth A, Scholes ments at the ecosystem and RJ, Nouvellon Y, de Grandcourt A, process level scale in Zambia, Archibald A, Bonnefond J M, Boulain N, Brueggemann N, Bruemmer C, Cappe- including the site specific distur- laere B, Ceschia E, El-Khidir H A M, El- bance regime. Some important Tahir B A, Falk U, Lloyd J, Kergoat L, Le Dantec V, Mougin E, Muchinda M, findings were that we observed Mukelabai M M, Ramier D, Roupsard O, no changes in soil respiration Timouk F, Veenendaal E M and Kutsch W L 2009a Precipitation as driver of between the undisturbed and the Figure 3: Crew during the installation of the lightning protection at the Mongu Fluxtower in carbon fluxes in 11 African ecosystems. Kataba Forest, Western Zambia. photocredit W. Ziegler degraded (logging, grazing and Biogeosciences 6, 1027-1041.

charcoal production) site in Merbold L, Kutsch W L, Corradi C, tion in regions receiving more clearly differentiate between C4- Zambia. When analyzing data Kolle O, Rebmann C, Stoy P C, Zimov S than 1000 mm of rainfall per and C -plant dominated ecosys- A and Schulze E D 2009b Artificial 3 spatially, another key result was drainage and associated carbon fluxes year. Respiration at sites receiv- tems from the obtained remote that there exists a close correla- (CO2/CH4) in a tundra ecosystem. Glob. ing less precipitation per year sensing data in relation to the Change Biol. 15, 2599-2614. tion between respiratory efflux was driven by water availability flux measurements. and soil carbon content, but not Zimov S A, Davydov S P, Zimova G M, in the soil. Additional to specify- During this time I realized that Davydova A I, Schuur E A G, Dutta K with meteorological variables and Chapin F S 2006 Permafrost car- ing primary drivers influencing carbon cycle research tends to nor total above- or belowground bon: Stock and decomposability of a globally significant carbon pool. Geo- carbon exchange, the study focus on natural “intact” ecosys- biomass. The gained knowledge phys. Res. Lett. 33. linked information found at the tem primarily, while disturbances can either be applied for further Merbold L, Mukelabai M M, Ziegler W ecosystem level using eddy co- and the accompanying changes in protection scenarios and/or be and Kutsch W L (xxxx) Spatial and temporal variation of CO efflux along a variance data to remote sensing ecosystem structure and there- applied for sustainable use of the 2 disturbance gradient in a miombo wood- products. This is important since fore also in carbon exchanges natural woodlands in Zambia land in Western Zambia. submitted to the network of long-term carbon are less understood for most (Merbold et al. submitted and Biogeosciences observation in Africa is still very ecosystems. Therefore I finalized Kutsch et al. in prep). limited. Eco-physiological inter- my thesis on the aspect of car- What’s next? I’ll continue work- Kutsch W L, Merbold L, Ziegler W, pretation of flux-tower data was bon exchange of highly seasonal ing on flux data; particularly data Muchinda M, Mukelabai M M and Scho- les R J (xxxx) Miombo forests and the achieved in connection to satel- environments (Africa and Sibe- collected during the three years energy needs of people: The Charcoal Trap. in preparation lite products as fAPAR. We could ria) under the aspect of anthro- of CarboAfrica and widen my Page 13

Investigating disturbance and recovery following a hurricane along the Everglades mangrove coast

Victor Engel, Jose Fuentes, Jordan Barr

Since 2003, we have investigated data acquisition system were experiences semi-diurnal tides, The tower base is 1.5 m above net ecosystem exchange (NEE) destroyed by winds and ~2. 5 m and tides reach up to 0.5 m the surface, and is supported by storm surge. We rebuilt the site above the surface. Peat thickness a square grid of central tiers of CO2 using eddy covariance (EC) above the largest contigu- and measurements resumed in above the karst bedrock reaches driven ~3 m into the sediment. ous mangrove forest in North November 2006. The storm 5 to 6 m. Annual minimum salin- Crossbeams to peripheral tiers America, found along the Gulf of provided a natural experiment, ity ranges from 2 to 18 parts per provide additional stability and Mexico coast in Everglades Na- and before and after Wilma trillion (ppt) during peak river prevent the structure from sink- tional Park. This coast is subject observations document hurri- discharge, and maximum salinity ing into the peat. to periodic hurricane distur- cane impacts on carbon cycling (30-35 ppt) occurs in May and bance, and this forest was im- in mangroves. June. Impacts of and recovery pacted by the Labor Day storm Construction of a 30-m flux from Wilma of 1935, Donna in 1960, and Site location and description tower (Figure 2) and a 250-m Prior to Wilma, annual net eco- o Andrew in 1992. The most re- The site (25.3646 N, boardwalk from the banks of system productivity (NEP) esti- o cent storm to hit this region was 81.0779 W) is located within a Shark River started in June 2003. mates for 2004-05 (1170 ± 145 g Hurricane Wilma in October riverine and fringing mangrove 2005 with sustained winds of forest close to the mouth of 176 kilometer per hour. The Shark River in western Ever- center of landfall was close to glades National Park (Figure 1). our EC site. During the storm Dominant tree species reach the tower, instrumentation, and heights of 15-20 m. The region

Figure 1: The mangrove forest occupying the Gulf of Mexico coast in Everglades National Figure 2. The eddy covariance tower, seen here before Hurricane Wilma, extends ~10 m Park is the largest of its kind in North America. above the 20 m tree tops and is supported by a wooden platform built on a peat substrate 5 to 6 m thick. Page 14

Investigating disturbance and recovery following a hurricane

Figure 3. In October 2005, Hurricane Wilma inflicted heavy damage to the mangrove forest along the Gulf of Mexico coast in Everglades National Park (top panels, courtesy of Thomas J. Smith III, USGS) as depicted in these before and after comparisons. The storm resulted in near complete defoliation and 30% mortality of trees at the study site (bottom panels). EC measurements resumed in November 2006.

-2 -1 C m yr ) were greater than respiration rates (RE) as a result mortality of mature trees at the irradiance, net radiation, air those reported for terrestrial of anaerobic conditions were EC site (Figure 3). Following temperature, and vapor pressure ecosystems (e.g., Baldocchi et al., also responsible for high NEP Wilma, we observed decreases deficit were not substantially

2001; Hirata et al., 2008). In Barr estimates. Nighttime RE values in daytime NEE. For example, different during these two peri- et al. (2010), we describe how varied from 1.71 ± 1.44 to 2.84 monthly composite diurnal NEE ods. A similar decrease in total -2 -1 tidal export of dissolved carbon ± 2.38 μmol (CO2) m s at soil trends showed that in April annual NEP was observed when is largely responsible for high temperature of 15 ± 2 oC and 20 2007, mid-day NEE was reduced post-storm values were com- o -2 -1 NEP estimates derived from EC. ± 2 C, respectively. These RE by 3 to 8 µmol (CO2) m s pared to pre-storm quantities However, in general the annual values are lower by a factor of 2 compared to April 2004 (Figure (Figure 5). The largest decreases NEP of tropical ecosystems is compared to terrestrial 4). Differences in pre- and post- occurred during 2007 and 2008, greater than that of temperate AmeriFlux and EuroFlux sites storm NEE values were not and by 2009, the differences ecosystems due to year-round (Falge et al., 2001). attributed to inter-annual differ- between pre- and post-storm productivity (Luyssaert et al., The storm defoliated much of ences in the local climate. Envi- annual NEP values had declined. 2007). Relatively low ecosystem the forest and resulted in ~30% ronmental drivers such as solar Such results indicate the state of Page 15

Investigating disturbance and recovery following a hurricane

ecosystem recovery. Reductions in NEP were medi- ated via several intrinsically re- lated processes. First, following defoliation and tree mortality, there was an immediate reduc- tion in physiologically active biomass. Second, litter and woody debris from downed limbs and stems were generated by the hurricane. Decomposi- tion of this material contributed to forest respiratory fluxes. In response to loss of foliage in the upper canopy layers, increased penetration of solar irradiance resulted in a 1.8 to 3.6 oC in- crease in soil temperature, and a more aerated canopy further augmented respiratory proc- esses. The lower net productiv- ity values in the first few years after the storm were likely a result of both decreased foliage Figure 4 Higher nighttime respiration and reduced daytime uptake rates are apparent in net ecosystem CO2 exchange after Wilma. and enhanced respiratory proc- esses. In the first year of measurements following the storm, annual NEP was reduced by 33% compared to 2004, with an 8% reduction in

GPP and a 21% increase in RE (Figure 6). To differentiate the direct effects of the storm from those induced by inter-annual climate variability we employed multivariate ridge-regression models relating monthly NEP,

GPP, and RE to environmental variables. The model was condi- tioned on pre-storm data and then used to generate post- storm estimates of monthly NEP,

GPP, and RE based on environ- mental conditions recorded in 2007-09. The disturbance caused a reduction of at least 1100 g m-2

Figure 5 A running summation of daily NEP shows large differences in the magnitude of annual carbon uptake by the forest before and after in NEP during these three years. Wilma. Recovery is apparent in the partial return in 2009 towards pre-storm NEP values. RE remained significantly higher Page 16

Investigating disturbance and recovery following a hurricane

References

Baldocchi, D.D., et al., 2001. FLUXNET: a new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and ener- gy flux densities, Bull. Amer. Meteorol. Soc., 82, 2415-2434.

Barr J.G., Engel, V.C., Fuentes, J.D., Zieman, J.C., O’Halloran, T.L., Smith III, T.J., and Anderson ,G.H., 2010. Con- trols on mangrove forest-atmosphere carbon dioxide exchanges in western Everglades National Park. In revision, J. Geophys. Res. [Biogeo.]

Hirata, R., et al., 2008. Spatial distribu- tion of carbon balance in forest ecosys- tems across East Asia. Agric. For. Me- teor., 148, 761-775.

Luyssaert, S., et al., 2007. CO2 balance of boreal, temperate, and tropical forests derived from a global database, Global Change Biology, 13, 2509-2537.

Falge, E., et al. 2001. Gap filling strate- Figure 6. Monthly total NEP was lower and RE was higher in the years following Hurricane Wilma. The storm’s effects on GPP were less obvious due to rapid leaf regeneration and accelerated growth in the understory. gies for defensible annual sums of net ecosystem exchange, Agric. For. Me- teor., 107, 43-69. than pre-storm values through Our findings suggest increased 2009. GPP recovered more salinity can cause a decrease in contact: Ward, G. A., and Smith, T.J. III. 2007. Predicting mangrove forest recovery on quickly than NEP or RE, probably productivity, and therefore, in Victor C. Engel the southwest coast of Florida, in Sci- due to widespread epicormic leaf peat accretion. If peat accretion ence and the storms: the USGS response to South Florida Natural Resources the hurricanes of 2005, edited G.S. Farris regeneration and accelerated is lower than rate of sea level et al., pp. 175-182, U.S. Geological Office, Everglades National Park, growth in the understory. The rise, the survival of mangroves Survey Circular 1306. Homestead, Florida, USA . quick recovery of GPP to pre- may be in question. The before storm values reflects the adapta- and after Wilma data indicate tion of mangroves to frequent that hurricane impacts on carbon [email protected] disturbances. This recovery is cycling must also be considered consistent with the 4-year recov- in any long-term projections of ery to the universal “self- mangrove ecosystem function. A thinning” line of mangroves recent grant from the Depart- shown by surveys along the ment of Energy’s National Insti- Everglades coast following Hurri- tute of Climate Change Research cane Andrew (Ward and Smith, with collaborators from the 2007). Florida Coastal Everglades LTER (FCE-LTER), Thomas J. Smith III Implications and future di- (USGS) and Victor Monroy- rections Rivera and Robert R. Twilley Prior to the storm, our data (Louisiana State University) will showed canopy light use effi- help us address this issue. ciency decreases with increasing salinity (Barr et al. 2010). In the era of sea level rise, salinity at this site is expected to increase. Page 17

Impacts of beetle-induced forest mortality on carbon, water and nutrient cycling in the Rocky Mountains Elise Pendall, Brent Ewers, Urszula Norton, Paul Brooks, W.J. Massman, Holly Barnard, David Reed, Tim Aston, John Frank

Conifer forests across western have impacted over 600,000 dead by 2012 (Figure 1; Figure warming trends and drought North America are undergoing a hectares in northern Colorado 2). While bark beetles are native (Allen et al. 2010). A recent widespread mortality event me- and southern Wyoming (US to North American forests, the modeling study suggests that diated by an epidemic outbreak Forest Service aerial survey importance of insect outbreaks CO2 emissions from beetle- of bark beetles of the genus estimates), with the majority of on water, C and N cycling has induced lodgepole pine mortality Dendroctonus and their associ- mature lodgepole pine (Pinus increased in recent years as a in British Columbia, Canada may ated bluestain fungi (Ophiostoma contorta) and Englemann spruce result of past timber manage- be similar in magnitude as stand- spp.). As of late 2009, beetles (Picea englemanii) expected to be ment, fire exclusion, recent replacing fires (Kurz et al 2008).

Figure 1: Current bark beetle activity in Wyoming Page 18

Impacts of beetle-induced forest mortality

knowledge. Furthermore, suc- cessional trajectories at upper and lower forest boundaries may not be predictable from stand dynamics of the recent past. On annual to decadal timescales, the responses of C, water and nutri- ent cycling to the beetle epi- demic are linked to forest stand dynamics, particularly leaf area index (LAI), as suggested by our hypotheses, presented in Figure 4. Near our study area in the Medi- cine Bow Mountains (Figure 1), beetle attacks were simulated by girdling trees on small experi- mental patches with the main objective of studying effects on water and N cycling. The girdling treatment increased discharge Figure 2. View of middle-elevation lodgepole pine forest in foreground, Medicine Bow range in background. Photography by Josh King. below the rooting zone (Knight Experimental girdling of lodge- cially important due to its large lieve that lodgepole pine is likely et al. 1991). Extensive spruce pole pines led to a 92% increase spatial extent, its timber, recrea- to become re-established follow- beetle mortality was associated in water outflow, compared to a tional and wildlife habitat values, ing bark beetle mortality (Jenkins with increased streamflow in 277% increase resulting from and its controls over carbon, et al 2008), but the rate of re- Colorado (Bethlahmy 1974) and clearcutting (Knight et al. 1991). water and nutrient cycles in mid- covery and resulting stand den- Montana (Potts, 1984). How- Despite the enormity of the elevation forests of the central sity and productivity are impos- ever, other key components of currently spreading bark beetle Rockies (Knight et al. 1991) sible to predict with current the water cycle, such as epidemic, little is known of its including southern Wyoming. impact on carbon, water and Beetle mortality of Englemann nitrogen cycles. spruce is a concern in subalpine Bark beetles spend much of their forests, where snowpack accu- life as larvae under the bark of mulates in the headwaters of host trees, feeding on phloem. rivers that supply Western cities Although healthy host trees can with most of their water. repel beetles through enhanced While predictive understanding resin production, the trees’ of the bark beetle epidemic is defenses are overwhelmed by improving, much less is known mass attacks synchronized by about its subsequent impact on pheromones. Tree death occurs plant succession and carbon, through occlusion of xylem by water and nutrient cycling. Much blue-stain fungus carried by the of the current understanding has beetles, resulting in death of been hypothesized from com- trees within months of attack parisons to fire research or Figure 3. Center, beetle close-up (~2-mm length) and sapwood in the cross-section stained (Figure 3; Knight et al. 1991). simulated with models (Kurz et with bluestain fungus. Tree on left is covered with the typical “popcorn” where the tree has While the beetle has several al. 2008). Forest managers be- “pitched out” the beetles by exuding resin. In mass attacks, enough beetles survive in the trees to lay eggs and the subsequent generation kills the tree as the bluestain fungus residing hosts, lodgepole pine is espe- in the larval gut occludes the xylem. Brent Ewers photos. Page 19

Impacts of beetle-induced forest mortality Litterfall, NEE

Rh,

DOM

export Interception,

LAI, N

availability temp

moisture,

Soil

Time since beetle attack

Figure 4. Postulated time course of ecosystem characteristics and biogeochemical responses to MPB attack over 3 year study period in our catchment ecosystems. MPB preferentially kills larger diameter host trees in open stands, leading to spatial variability in mortality patterns and impacts (indicated by dashes). TOP: Tree mortality is associated with rapid loss of LAI, decreased Transpiration, NPP and canopy interception (yellow). A pulse of needle litterfall begins during the second year after attack, and is associated with peaks of decomposition (Rh) and DOM export to streams (blue). BOTTOM: Decreased LAI and transpiration lead to Figure 5. Canopy transpiration with and without beetle/fungus attack from GLEES. increases in soil moisture and temperature (red). Reduced N uptake by trees enhances N availability (green), which may be inhibited by terpenes the first year after attack. potentially enhancing growth and (Figure 6a, b). The GLEES evapotranspiration, have not N cycling. Parsons et al. (1994) C sequestration, or lost to Ameriflux site (41.36642° N ; previously been studied. Our found that girdling patches with streams or denitrifying processes 106.23995° W; 3126 m) has initial sap flux data suggests that at least 15 trees resulted in sig- is still unknown. been in operation since 1999, within a month of beetle attack nificantly greater concentrations We are studying ecosystem and is dominated by Englemann and introduction of bluestain of inorganic N while dissolved responses to beetle-induced spruce and subalpine fir (Abies fungus, transpiration per tree is organic N decreased. Indeed, lodgepole and spruce mortality lasiocarpa). Recent data from reduced to less than half (Figure surviving trees are crucial to at middle and upper elevation GLEES suggest a decline in forest 5). Water availability following retaining N in stands (Knight et forests using eddy covariance at C uptake and water loss (Figure beetle attack is likely to deter- al. 1991). How much of this Chimney Park (CP) and the 7). The CP site (41.068° N, mine in large part the immediate extra available N will be taken up Glacier Lakes Ecosystem Experi- 106.1195° W 2740 m elevation) responses of subsequent C and by the next generation of trees, ments Site (GLEES), Wyoming has been operating since spring, Page 20

Impacts of beetle-induced forest mortality

Figure 6. A. GLEES AmeriFlux scaffold; B. CP tower.

2009, and is dominated by lodge- that during the 2009 growing the carbon and water budgets at succession. Past timber manage- pole pine that has been sub- season, mortality had not yet the tower scale as well as in zero ment appears to have affected jected to varying management impacted water or CO2 fluxes. A - and first-order drainages via the rate of infestation and extent regimes in the past several dec- unique aspect of our study is intensive studies of snow hydrol- of mortality, and will thus also ades. Preliminary data suggest that we are attempting to close ogy (Figure 8), soil water, respi- impact regeneration. Our pre- ration and trace gas fluxes within sent focus is on short-term (3- 75 0 stands varying in time since bee- year) responses to the current CO tle attack. bark beetle outbreak and will set

1 70 -1 2 ‐ Clearly, many unknowns exist the stage for continued longer- –Mg yr regarding forest regeneration term monitoring (5-10 years and 65 -2 beyond). Our study areas are cm and C, N and water cycling fol-

C ‐

lowing beetle attack. Regenera- valuable because of their prox- ha

O 60 -3 2 tion, or succession, will define imity accessibility in all seasons, ‐ H 1

55 -4 yr the trajectory of forest stand and extensive ecological re- ‐

1 dynamics for the coming cen- search that has been previously 50 -5 tury, and the plant communities conducted there (e.g., Knight et that are established in the wake al. 1991; Parsons et al. 1994; 2005 2006 2007 2008 2009 2010 of the epidemic will regulate Musselman 1994). Thus, we YEAR biogeochemical and water cycles expect that this initial study over the decadal time frame of should generate mechanistic Figure 7. Annual CO2 and H2O fluxes from the GLEES AmeriFlux site (negative means uptake by the forest ecosystem). understanding of immediate Page 21

Impacts of beetle-induced forest mortality

References

Allen, C.D. et al. 2010. A global over- view of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecology and Management, 259(4): 660-684.

Bethlahmy, N. 1974. More streamflow after a bark beetle epidemic. Journal of Hydrology. 23:185-189.

Jenkins MJ, Hebertson E, W Page, CA Jorgensen. 2008. Bark beetles, fuels, fires and implications in the Intermountain West. Forest Ecology and Management 254:16-34.

Knight DH, JB Yavitt and GD Joyce. 1991. Water and nitrogen outflow from lodgepole pine forest after two years of tree mortality. Forest Ecology and Management 46:215-225.

Kurz WA, CC Dymond, G Stinson, GJ Rampley, ET Neilson, AL Carroll, T Ebata, L Safranyik. 2008. Mountain pine beetle and forest carbon feedback to climate change. Nature 452:987-990.

Musselman, R. C., technical coordinator. 1994. The Glacier Lakes Ecosystem Experiments Site. Gen. Tech. Rep. RM-249. Fort Collins, CO: U.S. Depart- ment of Agriculture, Forest Service, Figure 8. Approaching Chimney Park tower in April, 2010, shows high lodgepole mortality especially along the edges of the trail. Ongoing work Rocky Mountain Forest and Range is documenting the progression of red trees, needlefall, and seedling re-establishment within stands surrounding the tower as drivers of ecosys- Experiment Station. 94 p. tem fluxes. Paul Brooks photo. Parsons WFJ, SL Miller and DH Knight. ecosystem responses and also 1994. Root-gap dynamics in a lodgepole pine forests: ectomycorrhal and nonmy- provide a platform for future corrhizal fine root activity after experi- studies. mental gap formation. Canadian Journal of Forest Research 24:1531-1538.

This research is supported by Potts DF. 1984. Hydrologic impacts of a large-scale mountain pine beetle the National Science Foundation, (Dendrotonus ponderosae Hopkins) US Forest Service, Wyoming epidemic. Water Resources Bulletin 20:373-377. Agricultural Experiment Station, and Wyoming Water Develop- USDA 2010 (http://www.fs.fed.us/r2/ mbr/resources/BarkBeetles/index.shtml, ment Council. 4/12/10) contact:

Elise Pendall [email protected]

Department of Botany & Program in Ecology, University of Wyoming,

Laramie

Page 22

Correspondence A tribute to Laurent Misson

A letter to “Speedy” Ray film “Rebel Without a Laurent. Cause,” in French, “La Fureur de I don’t remember precisely when Vivre.” The film leaves a senti- and where we first met. Perhaps ment of disillusionment. This you were preparing your re- sentiment hasn’t left me since search project for CNRS? Or your departure. I will miss you perhaps you were doing a post very much. I miss you already. doc at Marseille modeling the S radial growth of Mediterranean Serge Rambal trees? Convincing the CNRS of your enormous potential as a researcher was not easy. Your initial project seemed to them to be too ambitious. My role was to help you reduce its scope. Your arrival from UC Berkeley to the DREAM team in Montpellier gift for me, without any expecta- profoundly influenced our nor- tion in return. He simply cared mal habits. The graft worked The minute I got introduced for others. He thought he could marvelously. The construction of to Laurent, I felt I just met a help me and that was enough of a rainout shelter – your rainout new friend...and I was right. a reason for him. shelter – demonstrated once Back then; I wanted to learn again your desire to push the more about plants in arid condi- Because I live in Montpellier part boundaries. Between my modest tions, since that is where most of of the year, I took care of him initial project design and your the good vineyards are grow- when he got appointed to the final realization of it rests the ing. However, with my wine- CNRS and moved back from incredible amount of energy you maker background, it was really Berkeley to France. Within a few deployed. When I think of you, I hard to be taken seriously by the weeks Laurent had become the can’t help think of the Nicolas scientific community, and even friend of all my long time friends; harder to get enrolled into a he was organizing documentary PhD program. Laurent was the sessions to discuss politics and first person who carefully lis- improve social awareness in the tened to me. He made me feel community. People from every that everything I wanted was social layers gravitated around possible. He helped me refining him; with Laurent I met politi- my ideas and he explained to me cians, artists, professional climb- how sap flow could be used to ers and salsa dancers as well as quantify the severity of water famous scientists. Life was fun deficit. Laurent shared his office around Laurent. I wish to be with me, taught me how to per- able to live my life according to form field measurement and was the standards he inspired in me. the main person helping me Laurent Misson was a real men- throughout my thesis writing. I tor. was amazed by so much gener- osity. All his actions were a true Thibaut Scholasch Page 23

A tribute to Laurent Misson

Laurent passed away already cause mine was good, probably nonetheless I felt proud that he, We spent some good scientific a month ago, and some of us trying to keep my ego at the such a bright guy, would take my conversations. He was continu- had the opportunity to say right level. Even if the guy meant opinions and thoughts into ac- ously, almost obsessively, updat- goodbye to him in Nor- to keep the ego of a young sci- count. At the moment he was ing his knowledge with new mandy, together with his entist under control, he was actually working on writing pa- literature in his field. He read a family and friends. When our always, or almost always, able to pers with the data obtained from lot before he started writing a common friend Jeff told me the face challenges with his good the last year water exclusions. paper. At the moment he did a terrible news, that Friday 5 sense of humor, very particular, He shared with me some of the lot of his reading also on ecology March, I could hardly believe very Laurent. Laurent has a big results obtained so far, how and ecological theories and in- him. The sudden and absurd presence in all the memories I these holm-oaks were able to formed me about this disappearance of a dear, irre- have from this period of my life. I avoid the water stress. Hopefully “hierarchical theory” he was placeable, friend, the most en- could hardly imagine California his students or colleagues will at really interested in, thinking on thusiastic and energetic person without remembering him. We some point be able to take over further developing a theory that I’ve ever met and one of the worked together, we laugh, we his ideas and ecological vision so at the moment was only this, most involved, bright and hard- had party, we fight….but even if we all will benefit from his effort. theoretical. Actually he sounded worker ecologist of his genera- we had our personal problems at I am sure he would be happy of to me a bit cryptic at that point. tion, has changed somehow my some point, we were actually that.. I remember I thought I would conception of life. Life seems a able to get over them and con- read a bit about this theory bit more absurd now. tinue our friendship and scientific collaboration. Laurent, was a singular guy, full of contrasts, half Belgian, half I spent a couple of days with French, world citizen, noble Laurent and Leyla in Montpellier inheritance but a bit of a gypsy, a month before this terrible an adventurer, funny guy, strong thing happened. Laurent and I temperament, good friend, smart had some articles to discuss and ass…we actually did not have some ideas for future articles. too many things in common, He showed me the huge rain- probably our common interest exclusion roof he and the team in understanding things and the built in the experimental site of pursuit for knowledge. He was Puechabon. He was really proud interested in whatever kind of of his rain exclusion experiment knowledge, from science to and spend sometime to explain politics or economics; naviga- me in detail, also how much tion….I was always interested on energy he and the people of the listening to his ideas and team invested on the design and thoughts. construction of this, the largest rain-exclusion roofs I’ve ever Laurent and I met the first time seen. He told me his idea of the in Berkeley; he was actually re- roof begun to take shape in sponsible of my arrival in the some conversations we had in an biometlab together with Dennis Ameriflux meeting in Boulder Baldocchi. He used to remind together with the two Alex, a me that the reason he actually couple of years ago. I don’t choose my CV was because the know at which extent I really other’s were very bad, no be- contributed to this idea, but Page 24

A tribute to Laurent Misson

before I try and get some more info of what was in his mind. If I have to describe our scientific relation with an ecological term I would say it was a “facultative mutualism”.

One thing that struck me from Laurent was that even if he had the position to delegate field work, he was still doing lot of it on his own. I think he just liked a lot to go to the field, spend time in the woods, taking a lot of pleasure of his job. He really loved what he was doing. He was a hard-worker, he always complained I was a lacy guy....probably true, but actually he sometimes made me kind of nervous with his energy and his to any endeavor, be it a climbing willingness to work. Truly, I have been avoiding amazing is the sheer number of trip, a dinner, or a hard day in writing this note. On some people that he has affected, the field. It’s difficult to think His memory is still very present level, I suppose, I am still in whom he has worked with, and that a person that is such an in the day to day life, not only denial of the fact that a per- whose lives he enriched along embodiment of the concept of because his name is on some of son whom I consider my the way. He has always played Joie de vivre is not going to pop the articles I am working on mentor, colleague, and down his role in the project we up on the phone or through right now, but also because my friend, is gone. I met Laurent worked on together, but he was Skype and start his usual way to think and my vision of life in 2002, when I was just starting instrumental in running an amaz- “What’s up, dude! So, listen, I has been somehow influenced by my PhD research. To say that ing team, and helping the people was thinking….” I talked to him his spirit. he was instrumental in my work on that team deal with both a couple of months before the is to say very little indeed; scientific and personal troubles. accident through Skype, we Laurent was my unofficial advi- He helped me through some of discussed a revision of our main Jorge Curiel Yuste sor, and the main force behind the most challenging times of my paper on Blodgett, and my up- my research. After Rodrigo life, and did it completely self- Vargas contacted me with the coming trip to Europe, and we lessly. I could go on and de- news, I sat there and thought of were planning to see each other scribe all the little moments, but the thousands of emails that this summer. It’s odd that it will there would be far too many to we’ve exchanged back and forth, always be the last time I saw him. fit here. Suffice it to say that I

of the dozens of meals that we Laurent’s contribution to the would have never become the shared in Berkeley and in the field of climate change science is person that I am today, to a cabins at the Blodgett station, of significant and wide-ranging, but large extent, if it was not for the tons of soil that we dug that is no secret and not a big Laurent’s friendship and support.

preparing the experiments, and surprise, given the amount of He will be missed more than of the hundreds of laughs we talent and energy that he words can describe. shared along the way. Laurent brought to his work. What is always brought 100% of himself Alexander Gershenson Page 25

A tribute to Laurent Misson

My memories are full of lier and realized how his vision want to let invisible boundaries FluxLetter restrict him to a shallow life. wonderful moments I shared and thoughts come true. Well, it The Newsletter of with Laurent, particularly was not only his vision, but also Berkeley was an inspiring envi- during our common years in his strong personal involvement, ronment and Laurent was always FLUXNET

Berkeley. When I came to getting up early in the morning, driving us to challenge our per- Berkeley, Laurent was already doing field work, working hard ception in science and beyond Vol.3 No.1 April, 2010 there, in a different group, and always with an enthusiastic science. I remember the moment though, but at the same building smile on his face, enjoying what when he tried to talk a group of FluxLetter is produced and with similar research inter- he was doing. us, his friends, into building with quarterly at the FLUXNET Office with support from the ests. His never-ending energy him a startup company on envi- National Science Foundation. pulled me into new exciting He was not only an inspiring ronmental consulting at interna- fields of thinking, both scientifi- scientist driven by an outstanding tional level. We even went for a cally as well as personally. I re- amount of curiosity and determi- little workshop on Berkeley member very well, when more nation, but also a very close campus on how to build start than five years ago Laurent – friend. He made my years in ups. At the end, the idea did not fascinated by his research find- Berkeley very special, a memory realize and we continued to be ings in California – pulled to- I will carry with me for the rest pure scientists, but it taught me gether a group of young scien- of my life. We worked on sci- how inspiring unrestricted think- tists to think about new experi- ence, analyzed data and wrote ing can be, a gift that Laurent had mental ways on how to investi- papers, but we also experienced and happily shared. gate the impact of extreme life in California, went to the events such as droughts on plant mountains and deserts, sailed, My thoughts are with Leyla, his -soil interactions and carbon and explored San Francisco. I am wonderful fiancée he met during cycling. He was driven – occa- now looking through many, our shared years in Berkeley, sionally even like crazy - and I many pictures and see how and his family in France and have to admit, sometime it was Laurent laughed and smiled and Belgium. Laurent, I miss you. hard for me to keep up with his how he brought smiles to me, to pace. Later then, I saw the im- others. Laurent once told me Alexander Knohl pressive facility on whole- that he wanted to live every ecosystem rain exclusion he built moment of his life and didn’t in Montpel- This issue of FluxLetter was edited, designed and produced by:

Rodrigo Vargas Dennis Baldocchi

FLUXNET Office, 137 Mulford Hall, University of California, Berkeley, CA 94720 ph: 1-(510)-642-2421 Fax: 1-(510)-643-5098 [email protected]

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