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Western North American Naturalist 67(1), © 2007, pp. 51-56

SURVIVAL AND SPROUTING RESPONSES OF AFTER THE RODEO-CHEDISKI FIRE ON THE MOGOLLON RIM,

Kenneth H. Baumgartnerl and Peter Z. Fulel .2

ABSTRACT.---Chihuahua (Pinus leiophylw Schiede and Deppe var. chihuahuana Engelmann) were surveyed on 11 study plots on the Mogollon Rim in east central Arizona to compare characteristics of that sprouted from the base or root collar after the Rodeo-Chediski fire with thosc of trees that did not sprout. The differences in trees killed and top-killed by the nre versus those that survived were also assessed. Trees that sprouted were Significantly smaller in height and diameter at breast height; they also experienced lower fire intensities than trees that did not sprout. Smaller trees had higher incidences of mortality than larger trees. These results indicate that, even though Chihuahua pine has fire resiliency, sprouting rates after firc are related to size of trees, age of trees, and burn intensity. Since Chihuahua pine is a rare species in the area studied, its ability to recover from and tolerate fire could prove advantageous for sus­ tainability.

Key words: Chihltahua pine, sprouting, vegetative reproduction, fire resilience, fire resistance, fire ecology, regenera­ tion, pine.

Pinus leiophylla Schiede and Deppe var. (USDA Forest Service 2002). This fire, which chihuahuana Engelmann (Chihuahua pine) is burned portions of the Mogollon Rim, provided one of the few pines that sprout in response to the opportunity to assess post-fire sprouting disturbance. This species can sprout both from characteristics of P leiophylla in an area where its base (Stone and Stone 1954) and from the it is rare, where it is the only pine species in stem or crown (Farjon and Styles 1997). It is the area that sprouts following fire, and where considered a fire-resilient species, having a low it is at its northern latitudinal limit (Petrides to moderate tolerance to fire but an ability to 1992). Considering that large crown fires are regenerate rapidly through the mechanism of likely to continue occurring in the area (Cov­ sprouting (McCune 1988). The ability to sprout ington et al. 1994), response of this population is believed to be restricted to young and juve­ to fire has significant implications for sustain­ nile trees. Of all the North American pines, P ability of P leiophylla on the Mogollon Rim. leiophylla has the best ability to sprout from We asked 3 questions regarding the effects the base (McCune 1988). Mature trees have of fire on basal sprouting of P leiophylla in thick bark (Perry 1991), which may help insu­ stands burned in the Rodeo-Chediski fire on late cambial tissue from fire (Pavek 1994). the Mogollon Rim: (1) does age have an In the United States, P leiophylla grows in influence on the ability to resprout; (2) does southwestern New and southeastern fire intensity have an influence on the ability and east central Arizona on dry slopes ranging to resprout; and (3) docs tree age have an from 1524 to 2438 m in elevation (Petrides influence on survival? We assessed the results 1992). Pinus leiophylla is most commonly found of this study in the context of P leiophylla in the mountains of southeastern Arizona; management. however, it is rare and sporadic on the Mogol­ lon Rim in east central Arizona (Petrides 1992, METHODS Muldavin et at. 1996). In east central Arizona, the Rodeo-Chediski The study was conducted on the Rodeo­ fire burned approximately 189,000 ha in 2002 Chediski burn in the Black Mesa Ranger Dis­ and was the largest fire recorded in Arizona trict of the Apache-Sitgreaves National I:

lEcological Restoration Institute and School of Forestry, Northern Arizona University, Box L50l8. Flagstaff. ,JU 8601l. 2Corresponding auUlOr. E-mail: [email protected]

51 ...

52 WESTERN NORTH AMERICAN NATURALIST [Volume 67

N A X Study plots

.. Apache-Sitgreaves NF

o Rodeo-Chediski burn

1~~=;;;;;;/=='.-.,;;O=~20 Kilometers

Fig. 1. Map of study area in the Black Mesa Ranger District on the Apache-Sitgreaves National Forest.

near Heber, Arizona. The area receives an diameter at breast height (dbh), total height, average annual precipitation of around 44.3 height of live crown base, minimum and maxi­ cm and an average annual snowfall of 99.3 cm. mum char heights, whether or not the stem Average monthly temperatures range fTom sprouted, and number of basal sprouts. Incre­ _8.9° to 29.3°C, with the minimum occurring mcnt cores were taken from a subset of trces in January and the maximum in July (Western to determine ages. We assumed that the major­ Regional Climate Center 2004). Average ele­ ity of charred, recently killed trees wcre killed vation for all study sites was approximately by the Rodeo-Chediski fire. We also assumed 2092 m ASL (range 2027-2245 m). Soil infor­ char height was correlated positively with flame mation was derived from a Terrestrial Ecosys­ length and thus was an approximation of fire­ tem Survey (Laing et al. 1987). Study sites line intensity near the individual trees as in were located on Vdic and Lythic Haplustalfs Agee (1993). (C.A. Nelson, USDA Forest Service, personal Within each plot, we sampled subplots for communication, 2005), with parent material other ovcrstory trees, shrubs, and regeneration. derived from alluvium and sandstone. Trees Other overs tory tree species were identified and shrubs consisted of Chihuahua pine, pon­ within the northeast quadrant and diameters derosa pine (Pinus ponderosa Laws.), white fir at breast height were measured. A 5 x 1O-m (Abies concolor Gord. & Glen.), alligator juni­ shrub plot originating from the northeast cor­ per ( Steud.), Gambel oak ner was used to tally live and dead shrubs and (Quercus gambelii Nutt.), pointleaf manzanita tree regeneration. The heights of shrubs and (Arctostaphylos pungens Kunth), and Fendler regeneration werc recordcd into 3 height ceanothus (Ceanothus fendleri Gray). classes: 0-40 cm, 41-80 em, and 81-137 cm. We selected 11 study plots based on known We took photos at each plot from the north­ locations of P. leiophylla. Plots were located east corner facing into the plot center. UTM over a distance of approximately 37 km (Fig. coordinates were recorded at the northeast 1). Due to the rarity of P. leiophylla in the area, corner. Plot aspect and slope were recorded. it was necessary to locate plots in a subjective Plots were corrected for slope in the field. manner. We chose sample plots in arcas where Data were analyzed with JMP (release P. leiophylla was in greatest abundance and 5.0.1.2; SAS, Inc., Cary, NC). We compared made an effort to include a variety of tree sizes characteristics of sprouting and nonsprouting and sprouting responses. Each plot was 50 x trees including diameters, total heights, and 20 m and permanently marked with an iron minimum and maximum char heights. Diame­ stake at the northeast corner. Every P. leio­ ters of trees that survived the fire and trees phylla individual was sampled regardless of that did not were also compared. Most data size, due to the ability of very young (small) were found to ha\'e nonnormal distributions trees to sprout. For each tree, we measured the and unequal variances, but these problems were following attributes: condition (livc or dead), corrected with square-root transformations. 2007] CHIHUAHUA PINE SURVIVAL AND SPROUTING 53

TABLE 1. Average tree density of Pinus leiophylla and other tree species after the Rodeo-Chediski fire for the It study plots.

I Species Density (trees· ha- ) sx- Ivlinimum Maximum Pinus leiophylla Live 216 56.3 10 640 Dead 225 48.8 40 520 Total 441 55.7 170 720 Pinus ponderosa 262 120.3 0 1360 J unipertts deppeana 18 11.3 0 120 Quercus garnbelii 4 3.6 0 40

TABLE 2. Average basal area (BA) of Pinus leiophylla and other tree species for thc 11 study plots.

Species BA (m 2 . ha-I) Sx Minimum Maximum Pinus leiophylla Live 4.3 0.9 0.7 9.9 Dead 1.4 0.5 0 5.3 Total 5.7 0.8 L2 LO.7 Pinus ponderosa 3.0 1.6 0 16.8 Juniperus deppeana 0.2 0.1 0 1.6 Quercus gambelii <0.1 0 0 <0.1

A Welch ANOVA was used to test data with TABLE 3. Summary of li"e and dead (top-killed) P. leio­ unequal variances. phylla with basal sprouts for the 11 study plots. Summary statistics (/I = II plots) RESULTS Total trees sampled 441 Among living in the 11 plots sam­ Percent with basal sprouts 34 Percent live 39 pled post-fire, P. leiophylla and P. ponderosa Percent top-killed 61 were codominant. Pinus ponderosa density Averages was slightly higher than that of P. leiophylla, Percent sprouting (trees per plot) 37 but basal area was higher for P. leiophylla. Percent live 37 There was also a small amount of Juniperus Percent top-killed 63 deppeana and Quercus gambelii (Tables 1, 2), both of which were observed to be sprouting from the base in a manner similar to P. leio­ phylla. Arctostaphylos pungens and Ceanothus fendleri were the only shrubs we found. Arc­ ters were significantly greater for live trces tostaphylos pungens was the dominant shrub. than for dead and top-killed trees (t = 6.13, P We found a positive linear relationship (R2 < 0.0001; Table 4). = 0.6324, y = 4.493x - 4.2857, P < 0.0001) be­ Individuals of P. leiophylla that sprouted tween dbh and age of P. leiophylla. The oldest from the base had Significantly different char­ tree dated was 220 years old and the youngest acteristics fTom those that did not sprout. was 26 years old. Trees with basal sprouts were smaller in dbh Of all P. leiophylla individuals sampled, 34% (F = 61.42, P < 0.0001), shorter in total height sprouted from the base and 61% were top­ (F = 44.50, P < 0.0001), and had lower maxi­ killed in the fire. The averages on a per-plot mum char heights (F = 6.31, P = 0.0130) than basis were similar to the average of all trees trees that did not sprout (l-able 5). The major­ sampled (Table 3). The highest mortality rate ity of trees that sprouted from the base were of P. leiophylla occurred mostly in smaller dbh in the 0-5-cm diameter class (Fig. 3) and classes and was generally lower in larger dbh rel1ected the distribution of dbh (Fig. 2). The classes. There was no mortality in the 30-35- proportion of sprouting from dead trees cm or the 35-40-cm classes (Fig. 2). Diame- decreased with increasing dbh (Fig. 3). ....

54 WESTERN NORTH AMERICAN NATURALIST [Volume 67

80 TABLE 4. Differences in diameters of post-fire live and dead Pinus leiophylla for the 11 study plots. 70 Diameter (dbh; em) 60 l!! o live trees Minimum Maximum !! 50 • dead trees ~ Live 13.1 0.70 0.3 44.4 ~ 40 a. Dead 7.9 0.59 0.2 41.2 : 30 ...~ 20

10 This study also supports the observation of Perry (1991) that sprouting of P. leiophylla 0-5 54 10 10 -15 15·20 20-25 25·30 30-35 35-40 40-45 occurs mostly in young trees. This poses an Diameter class (em) important implication for management of forests containing this species. To have a favorable Fig. 2. Distribution of diameters at breast height of live sprouting response to fire, stands o[ P. leio­ and dead individuals of Pinus leiophyUa for the 1I study plots. Dead trees were killed by the fire. phylla should be managed to ensure that there are significant numbers of trees with diame­ ters at breast height <30 em. The observations in this study indicate that

45 P. leiophylla has certain distinct advantages compared to other tree species in the area. 40 Since P. leiophylla is the only sprouting pine 35 species on the Mogollon Rim, its ability to ~ 30 sprout as a form of regeneration [ollowing fire ~ 25 .c could be an important advantage over P pon­ i., 20 derosa. Because sprouting is not dependent ~ 15 upon a crop o[ seeds, P. leiophylla can regen­

10 erate even when all the trees in an area have been killed. This ability could potentially mean the difference between pines being dominant

0·5 5·10 10·15 15·20 20·25 in an area after fire versus dominance of Diameter class (em) another tree or shrub species. Pinus leiophylla also possesses a degree of fire resistance in mature trees. This may serve as an advantage Fig. 3. Distribution of diameters at breast height of live over other sprouting species that do not pos­ and dead trees that sprouted from the base after the Rodeo-Chediski fire for the 1I study plots. sess thick bark and are more easily top-killed, such as oaks. That P. leiophylla has shown considerable regeneration immediately after the Rodeo­ DISCUSSION Chediski fire has implications for tree diver­ sity on the Mogollon Rim. Currently, P. leio­ Consistent with McCune (1988), P. leio­ phylla is a rare species in the area, but given phylla demonstrated an ability to resprout the advantages mentioned above, it may likely from the base following the Rodeo-Chediski increase in abundance in the future. fire (Fig. 4A, 4C). Sprouting by P. leiophylla Though this study identified important traits following this fire occurred both from top­ related to sprouting, more extensive research killed trees and [rom live trees. For top-killed should be done on this species to assess the trees, however, sprouting was not uniform, be­ relationships between bark thickness and tree cause higher char height on trees, indicating age, size, and fire resistance; factors that cause greater fire intensity (Agee 1993), was associ­ or influence stem and basal sprouting; and ated with reduced sprouting response. This ability of sprouts to produce cones. The height, suggests that, though P. leiophylla is known to growth, and survival of basal sprouts should be resilient to fire, this resilience may be neg­ be studied over time to assess whether post­ atively influenced by increased fire intensity. fire sprouting translates into mature trees. Also, .... -

20071 CHIHUAIl UA P[N l': S URUVAL AN D SPRO UTlNC 55

TA BLE .5 . Diffe re nces in characl<:' ristics or sprouting and nonsprouting Pinus /cioph ylla ror the II stu ck pl ots.

.~ S.f ~fillirnunl ~l a, imulll Diameter (dbh ; cm) Sprouters 5. 7 0.46 0.1 2 1. 8 No nsprouters 1l.9 0.58 0.2 -14. .4 Total height (JII ) Sprollte rs 3 1 0.21 O. l 9.8 Nonsprollters 5.1 0.19 0.3 1.5.3 ~ [ ax imllm char he ight (m) Sprollte rs 125 0.1 3 O.l G.6 Nonsproute rs l.72 0.11 01 10.8

Fig. 4. (A) Single large basal sprout or PiIJus leiophylla ori gin ating rro m a jll\'enil e tree; (B ) thick bark 0 11 mature tree; (C) small tree with multiple small basal sprouts. 56 " rES'fERN N ORTH A~IEH.I C A. N NATURALIST [Volume 67 it would be interesting to compare the sprout­ L\ING, L. , N. A ~IB OS, T SUB IRGE , C. ~l c D oNAL D , C. NE L­ in g response to fire of P. leiophylla vvith the SON, AN D W. HOB BI E. 1987. Te rrestri'11 ecosystem survey of the Apache-Sitgreal'es Nati o nal Forests. sprouting responses of Q. gambelii and.f. dep­ U.S. De partme nt of Ag riculture', Forest Se rv ice, peana on the Mogollon Rim to assess post-firc Southweste rn Region, Albuque rq ue, N M. interactions of these specics. ~I CCUNE, B. 1988. Ecological diversity in North Ame ri ­ can pines. Ame rican Journal of Botany 75:353- 368. 1-I UL Dw IN, E.H ., R.L. D EVE LlCE, AND F. RONCO, J lI. AC K N O\VL E D G ~IE N T S 1996. A classificatio n of forest habitat types: south­ e rn Arizo na and portions of the Colorado Pl ateau. Many thanks go to Gayle Ri chardson of the USDA Forest Se rvice Gene ml Technical Re port RII- I­ Black Mesa Ranger District, Sitgreaves Nation­ GTR-287, Rocky ~Iount a in Fo rest a nd Hange Expe r­ al Forest, for her support of the project and ime nt Station, Fort Collins, CO. help in locating study sites. We thank Tom Kolb, P.\\·E K, D.S. 1994. Pinus leiophylla va l'. chilwahu([ II ([. Fire Effects Information Sys tem [Online]. US DA Forest Dave Huffman, Robin Long, Chris lv[cGl one, Se rvice, Rocky ~[ o unta in Research Stati on, Fire Sci­ tvl ark Danie ls, Don Normandin, and Mike e nces Laboratory, producer. Ava il able from: http:// Stoddard for their comments. We also greatly \\'\.\"v. fs. fecl .us/database/feisl. appreciate the help of Matt Tuten, Barb Strom, PERR Y, J.P. , J R. 199 1. The pines of Mex ico a nd Central Am erica. Timbe r Press, Portland, o n. Amanda Kuenzi, Stephanie Smith, Je ff Rainey, PETRID ES, G. A. 1992. A fi e ld guide to weste rn trees: west­ Lang Sub)', and Cam Altree. ern United States and Canada. Pe te rson Fi eld Guide Series. Houghton ~ lil11in . LITERAT URE C ITED STONE, E. L. , J R., .\ND ~I . f!. ST00l[. 195-1 . Root colla r sprouts in pine. Journal of Forestry .52:487--19 1. AGEE, J.K . 1993. Fire ecology of Pacific Northwest forests. [\\"H.CC] W ESTERN REG IONA L G U ~I.\T E CENTER. 200-L [sla nd Press, 'vVashington, DC. Hebe r Ranger Station, Arizona: Pe ri od of record monthly climate summa,y. Asailable fro m: http://w,,,,,,. COI INGTON, W\V, R. L. EI ' E R ETI ~ R. STEE LE, L.L. [ 1\1\ 1:\, T.A. DAE R, AND A. N. D. AUC LAIH. 199-1 . Historical and \\TeC .dri .edu/cgi -bi n/cli M A[ N. pl '?azhebe a nticipated changes in fo rest ecosyste ms of the in ­ US DA FOll EST SE RI·ICE. 2002. Hodeo-Chediski fire e ffects sutllmary re po rt. Unp ublished d ata on fil e with la nd \Vest of the United States. Journal of Sustain­ abl e Forestry 2(1-2): 13-63. Apache-Sitgreaves Nati onal Forests, Springcn'ille, FAR IO!\", A., AND B.T. SHLES. 1997. Pinus (). Flora AZ Neotropica: ~'1 o n og raph 75. Organization for Flora Neotropiea. The New York Bota ni cal Garde n, New Receiced.3 March 2005 York. Accepted 8 August 2006