Decline of Red Spruce in the Green Mountains of Vermont Author(S): Thomas G
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Decline of Red Spruce in the Green Mountains of Vermont Author(s): Thomas G. Siccama, Margaret Bliss and H. W. Vogelmann Source: Bulletin of the Torrey Botanical Club , Apr. - Jun., 1982, Vol. 109, No. 2 (Apr. - Jun., 1982), pp. 162-168 Published by: Torrey Botanical Society Stable URL: https://www.jstor.org/stable/2996256 JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms Torrey Botanical Society is collaborating with JSTOR to digitize, preserve and extend access to Bulletin of the Torrey Botanical Club This content downloaded from 128.228.0.65 on Fri, 09 Apr 2021 01:23:36 UTC All use subject to https://about.jstor.org/terms B U L L E T I N O F T H E T O R R E Y B O T A N I C A L C L U B VOL. 109, No. 2, pp. 162-168 APRIL-JUNE, 1982 Decline of Red Spruce in the Green Mountains of Vermont Thomas G. Siccama Yale School of Forestry and Environmental Studies, New Haven, CT 06511 Margaret Bliss and H. W. Vogelmann Department of Botany, University of Vermont, Burlington, VT 05405 SICCAMA, T. G. (Yale School For. Env. Stud., New Haven, CT 06511), M. Bliss and H. W. Vogelmann (Dept. Bot. Univ. Vermont, Burlington, VT 05405). Decline of red spruce in the Green Mountains of Vermont. Bull. Torrey Bot. Club 109: 162-168. 1982.-Red spruce (Picea rubens Sarg.), a potentially long lived (>300 yrs) shade tolerant major forest species of the re- gion, declined by about half in basal area and density in virgin mid to high elevation stands in the Green Mountains of Vermont between 1964 and 1979. The decrease is not logically related to forest successional development and no specific causes have been documented. Diminished growth rates and general low tree vigor in 1981 indicate that the decline is continuing. Keywords: Picea rubens; Vermont; population dynamics; dieback; montane boreal forest Red spruce (Picea rubens Sarg.), a long- instability (Siccama 1974). Above 880 m lived (>300 years) shade-tolerant species, and extending to the alpine vegetation at Hart (1959), is a major component of forests 1230 m on the peaks, the boreal forest is of mid-upper slopes of the Green, White dominated by balsam fir and red spruce. and Adirondack Mountains (Siccama 1974; Red spruce is most abundant in the upper Bormann et al. 1970). During the past two transitional forest and lower boreal forest. decades the increasing rate of mortality of individuals of all size classes and lack of Methods. The forest on the west slope reproduction of red spruce has been ob- of Camels Hump (Huntington, VT) was served by us throughout the forests of cen- the primary study area with additional data from less intensive studies of the west tral and northern New England. In this slope of Mt. Abraham (22 km south of paper we report on quantitative changes of red spruce populations over a 15 year pe- Camels Hump), Bolton Mountain (14 km north of Camels Hump) and Jay Peak (70 riod (1964-1979) in the Green Mountains of Vermont. km north of Camels Hump). All these sites Forest vegetation on slopes of the are on the west side of the north-south trending axis of the Green Mountains that Green Mountains occurs in 3 fairly distinct elevational zones. Below 760 m sugar stretch from Canada through Vermont to Massachusetts. maple (Acer saccharum Marsh.), beech (Fagus grandifolia Ehrh.) and yellow birch A study of the forests on Camels Hump, Jay Peak, Bolton Mt. and Mt. Ab- (Betula alleghaniensis Britt.) are dominant with red spruce as a minor, but common raham in 1964 was followed by an inten- associate. Between 760 and 880 m the forest sive study on Camels Hump in 1965 (Sic- is transitional to the higher boreal forest. cama 1974). The Camels Hump forests were restudied in 1979 as were forests above Sugar maple, beech, yellow birch, fir (Abies balsamea (L.) Mill.), red spruce and 760 m on the other 3 mountains. white birch (Betula papyrifera Marsh.) The specific location of the original dominate in a mosaic of age classes and stands studied on Camels Hump was well compositional patterns reflecting climatic established and the plots laid out in 1979 were within the same hectare area as were those in 1965. Although permanent plots Received for publication July 23, 1981. were not used, our thorough knowledge of 162 0040-9618/82/02-0162-07$01.05/0 ? 1982 Torrey Botanical Club This content downloaded from 128.228.0.65 on Fri, 09 Apr 2021 01:23:36 UTC All use subject to https://about.jstor.org/terms 1982] SICCAMA ET AL.: DECLINE OF RED SPRUCE 163 the location of the stands from previous in- in annual radial growth of large, living red tensive studies permitted the location of spruces on Camels Hump were studied by the 1979 plots such that they were super- comparison of tree cores obtained in 1964, imposed on the same area of forest studied 1971, and 1980 from the boreal zone on previously and most certainly overlapped Camels Hump. the areas measured in 1965. Sampling of forests on the slopes of the other moun- Results and discussion. Since 1964, all tains in 1979 was made along a transect in size classes of red spruce have declined in the general area of the forest stands sampled density in higher elevations zones (transi- in 1964 and thus does not represent such a tion 760-880 m and boreal >880 m) of all close resampling of the same stands as was mountains studied (Table 1). In the hard- the case on Camels Hump. wood forest on Camels Hump (550-760 m) Tree stems >2 cm dbh were tallied by spruce declined by 68 percent in the species on 3.0 X 30.5 m (10 X 100 ft.) plots. smaller size classes (2-9 cm). Although the Dead and living stems were recorded sep- number of stems >10 cm did not decline arately in 1979, but dead stems were not (remained constant), basal area of this size counted in 1964 and 1965. Stems <2 cm class declined 42 percent indicating that dbh were recorded on 6 1 X 1 m plots laid mortality of larger individuals in this size out within each larger plot. Smaller size class occurred. It should be noted that red stems (<2 cm) were studied in 1979 only on spruce makes up a very small proportion Camels Hump. A total of 85 large plots of total stems in the hardwood zone, thus and 510 m2 plots were used on Camels our sampling intensity for trees >2 cm Hump for each sample year; 115 plots were only weakly measured the changes in this examined on the other mountains. Changes species in this zone. The reduction of 81 Table 1. Comparison of density and basal area of red spruce (Picea rubens Sarg.) in forests of the Green Mountains of Vermont in 1965 and 1979. DENSITY (Stems ha-') BASAL AREA (mi2 ha1') Size Class 1965' 1979 % Change Dead2 1965 1979 % Change Dead (cm) Boreal Forest (>880 m) Camels Hump <2 4211 2866 -32 - - - - - 2-9 206 151 -27 39 0.52 0.30 -42 0.09 >10 125 60 -52 73 6.32 3.51 -44 7.00 Other mountains (pooled data)3 2-9 256 73 -71 73 0.48 0.15 -69 0.17 >10 145 76 -48 66 3.17 3.22 +2 1.98 Transition Forest (760-880 m) Camels Hump <2 8748 4333 -50 - - - - - 2-9 495 145 -70 102 0.89 0.14 -84 0.18 >10 91 54 -41 65 5.73 3.42 -40 8.55 Other mountains (pooled data) 2-9 352 45 -87 54 0.79 0.08 -90 0.11 >10 124 9 -93 9 2.03 0.26 -87 0.10 Northern Hardwood Forest (550-760 m)4 Camels Hump <2 216 42 -81 - - - - - 2-9 16 5 -68 0 0.02 0.004 -80 0 >10 13 13 0 8 1.49 0.86 -42 0.56 'Camels Hump studied in 1965, other mountains in 1964. 2 Dead stems measured in 1979 only. 3Jay Peak, Bolton Mt., and Mt. Abraham. Stems <2 cm dbh were not tallied. 4Stands below 760 m were not resampled on other mountains in 1979. This content downloaded from 128.228.0.65 on Fri, 09 Apr 2021 01:23:36 UTC All use subject to https://about.jstor.org/terms 164 BULLETIN OF THE TORREY BOTANICAL CLUB [VOL. 109 percent in stems <2 cm and 68 percent in trees (>2 cm dbh) declined from 45 to 25 stems 2-9 cm as well as the fact that while per ha. No spruce seedlings were found in only 13 stems per hectare (>10 cm) of this either sampling period. species occurred, 8 dead stems occurred or In addition to the decline in numbers 38 percent of larger spruce stems are dead and basal area of red spruce, the species in the hardwood zone. also shows a decline in the radial growth The boreal forest on the west slope of of surviving individuals in the lower bo- Camels Hump has never been cut over.