uid=HFR,o=lter,dc=ecoinformatics,dc=org all public read doi:10.6073/pasta/da73d72739e2243aa7e86fb793cff76e David Foster https://orcid.org/0000-0003-1171-3762 Peter Schoonmaker Audrey Barker Plotkin https://orcid.org/0000-0002-4473-9785 Researcher Jesse DeNormandie Researcher Russell Stafford Researcher 2025 English

There are relatively few studies that have examined forest structure and composition both before and after a catastrophic wind disturbance has altered the forest. On a twenty acre parcel of old-growth forest located in the Pisgah State Forest in southwest New Hampshire, the collection of a long term data set from 1907-1995 has made it possible to consider how the hurricane of 1938 altered forest structure, species composition, and subsequent forest development in the stand. Various types of information were gathered throughout the century that allowed the quantification of forest structure and composition: species identification, diameter measurements, tree status (living or dead), tree cores, and individual tree growth and mortality have recently been tracked. The old-growth forest before 1938 was dominated by a Pinus-Tsuga-Hardwood mix. The hurricane left the forest devastated and incredibly altered. The total basal area of the forest was drastically reduced from approximately 70m2/ha to about 5m2/ha after the disturbance. White pine was effectively lost from the stand while many large Tsuga were also blown down. A large increase in density was subsequently recorded as many post-disturbance species took advantage of the resources that had been made available, especially light. Although there was a high level of destruction, a good amount of Tsuga and Fagus that had previously existed in the understory was released from suppression and grew to fill in parts of the overstory. Both the forest structure and the species composition changed from a relatively homogeneous state before the hurricane to an extremely heterogeneous one after the hurricane. The overall development of the stand followed the typical path of a recently disturbed area: after the initial increase in density in the few years after the storm, basal area has been steadily increasing while density has steadily decreased. It has also been possible to observe differences in the ability of individual species to react to the hurricane. Tsuga and Fagus are exhibiting a much-increased ability to remain in the stand while other post-disturbance species such as Betula and Acer are suffering much higher mortality. Although the forest already has very low tree species diversity, it will continue to drop with time as more and more of the post-disturbance hardwoods are lost to mortality.

hurricane damage old growth forests permanent plots regeneration vegetation dynamics LTER controlled vocabulary disturbance LTER core area Harvard Forest HFR LTER USA HFR default

This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.

Creative Commons Zero v1.0 Universal https://spdx.org/licenses/CC0-1.0.html CC0-1.0 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf041 Pisgah State Forest (NH). Coordinates based on WGS84 datum. -72.44 -72.44 +42.83 +42.83 1984 2024 ongoing Information Manager Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 hf-im@lists.fas.harvard.edu Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu

Data available on-line are from 14, 20m x 20m permanent plots established in 1984. Data collected include tree diameters, abundance of regeneration (saplings, seedlings and sprouts), understory flora abundance, and measurements of trees windthrown in 1938. Notes on tree measurements: There has been inconsistency in the methods used to record forked trees. The method used in 1984 is not known. In 1990 and from 2000 on, stems forking below breast height were listed as separate stems in the data files. However, in 1995, stems forking below breast height were lumped. In cases of forked trees, the diameter of each fork was measured and the sum of these was recorded as one diameter measurement on the field data sheet (e.g., in one case. a tagged birch in 1990 had a diameter of 12cm or so, in 1995 a diameter of 54cm and in 2000 of about 14cm. When the data sheet was checked, it just listed the diameter as 54 cm, stating in parentheses that this included 4 stems). Therefore, the stem counts in 1995 are not directly comparable to the other years, and the basal area calculations for 1995 are inflated. Original data sheets for 1995 and 2000 were examined closely and a revised version of the 1995 tree data was created. This revised file is the one included in the Web Data Catalog. In this revised file, diameters for all multiple-stemmed trees that could be found were split into separate diameter measurements, so that basal area calculations would be more accurate and data more comparable among sample years. However, since most trees are not tracked as individuals, it is likely that some problems still remain in the 1995 tree data file.

Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu https://ror.org/059cpzx98 pointOfContact The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts. National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210. hf041-01-tree.csv trees hf041-01-tree.csv 337564 cf0676f36bdc058fdbcf53c01ea261e8 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p04/hf041/hf041-01-tree.csv year year of measurement YYYY plot plot number. One of 14 20x20m plots. plot number species species code ACPE Acer pensylvanicum ACRU Acer rubrum ACSA Acer saccharum BEAL Betula alleghaniensis BELE Betula lenta BEPA Betual papyrifera FAGR Fagus grandifolia FRAM Fraxinus americana PIRU Picea rubens PIST Pinus strobus PRSE Prunus serotina QURU Quercus rubra TSCA Tsuga canadensis dbh tree diameter measured at breast height (1.37m). In 1984 and 1990, measurements are to the nearest cm. Thereafter, measurements are to the nearest 0.1 cm. centimeter 0.1 real NA missing value cond condition L living D dead vigor for hemlock trees only. Vigor rating is based on visual estimate of foliage loss. 1 0-25% foliar loss 2 25-50% foliar loss 3 50-75% foliar loss 4 75-99% foliar loss 5 dead tag tag number for the subset of trees that have tags; recorded beginning with the 2006 census tag number notes notes on individual trees (tag # for the subset of trees that have tags), tree health, etc. notes NA missing value 11288 hf041-02-regen.csv regeneration hf041-02-regen.csv 9169 a415ba2aec15e02f546062755aba529c 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p04/hf041/hf041-02-regen.csv year year of measurement YYYY species species code ACPE Acer pensylvanicum ACRU Acer rubrum ACSP Acer species or Acer spicatum? BEAL Betula alleghaniensis BELE Betula lenta BEPA Betula papyrifera BESP Betula species FAGR Fagus grandifolia FRAM Fraxinus americana NYSY Nyssa sylvatica PIRU Picea rubens PIST Pinus strobus PRSE Prunus serotina PRSP Prunus species QUAL Quercus alba QURU Quercus rubra TSCA Tsuga canadensis UNK unknown tree species size size categories varied by sample year. In 1984 and 1990, Saplings = stems 20 cm height to 2 cm diameter at breast height. Seedlings = stems less than 20 cm tall. In 1990 only, Sprouts = stems originating from dead tree bases or root sprouts (but of no specific size range). From 2010 onward, all and only stems under 1m tall were included. size categories varied by sample year. In 1984 and 1990, Saplings = stems 20 cm height to 2 cm diameter at breast height. Seedlings = stems less than 20 cm tall. In 1990 only, Sprouts = stems originating from dead tree bases or root sprouts (but of no specific size range). In 2010, all and only stems under 1m tall were included. plot plot number. One of 14 20x20m plots. plot number count abundance, for 1984 and 1990. Abundances listed are generally the total number of stems counted in each plot. In some cases, a species was noted but no count was listed; in these cases, presence of the species is indicated by an asterisk (*). In some cases, the number of stems was very numerous and the abundance is qualitatively listed as "many." Abundance data for saplings, seedlings and sprouts were collected in 1984 and 1990 (sprouts were not counted in 1984). abundance. Abundances listed are generally the total number of stems counted in each plot. In some cases, a species was noted but no count was listed; in these cases, presence of the species is indicated by an asterisk (*). In some cases, the number of stems was very numerous and the abundance is qualitatively listed as "many." Abundance data for saplings, seedlings and sprouts were collected in 1984 and 1990 (sprouts were not counted in 1984). NA missing value cover in 2010, cover classes rather than counts were recorded using the following 10-point scale * a single individual 1 1-2 individuals 2 less than 1% 3 B1-4% 4 4-10% 5 11-25% 6 26-33% 7 34-50% 8 51-75% 9 76-90% 10 91-100% notes notes notes NA missing value 276 hf041-03-under.csv understory hf041-03-under.csv 7355 114d54a0a7731a4aaf3d2a289900d3bb 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p04/hf041/hf041-03-under.csv year year of measurement YYYY species species code and unknowns ACTSPE Actea cr. pachypodium ARANUD Aralia nudicaulis ASTACU Aster acuminatus ASTDIV Aster divaricatus ASTSPP Aster species CARSPP Carex species (CARSPP2, CARSPP3 etc. if more than one distinct Carex species identified within a plot) CLIBOR Clintonia borealis CORALT Cornus alternifolia DENPUN Dennstaedtia punctilobula DIELON Diervilla lonicera DRYMAR Dryopteris marginalis DRYSPI Dryopteris spinulosa DRYSPP Dryopteris species EPIVIR Epifagus virginiana GAUPRO Gaultheria procumbens GOOSPE Goodyera species (likely tesselata) HAMVIR Hamamelis virginiana LONCAN Lonicera canadensis LONSPP Lonicera spp. LYCLUC Lycopodium lucidulum LYCOBS Lycopodium obscurum MAICAN Maianthemum canadense MEDVIR Medeola virginiana MITREP Mitchella repens MONUNI Monotropa uniflora POLACR Polystichum acrostichoides POLPUB Polygonatum pubescens POLVUL Polypodium vulgare RUBIDA Rubus idaeus RUBSPP Rubus species SAMCAN Sambucus canadensis TRIBOR Trientalis borealis TRIUND Trillium undulatum TRISPP Trillium spp. UVUSES Uvularia sessilifolia VACANG Vaccinium angustifolium VACcfVAC Vaccinium cf. vacillans VACSPP Vaccinium spp. VIBACE Viburnum acerifolium VIBALN Viburnum alnifolium VIBSPE Viburnum species Free text (unrestricted) .* plot plot number (1-14) plot number cover abundance of each understory species per plot, using the following 10-point scale (maximum cover observed was class 3) * a single individual 1 1-2 individuals 2 less than 1% 3 1-4% 4 4-10% 5 11-25% 6 26-33% 7 34-50% 8 51-75% 9 76-90% 10 91-100% notes notes notes NA missing value 340 hf041-04-wind.csv windthrow hf041-04-wind.csv 20411 9edf616f11714a60859b44a2882a7cb7 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p04/hf041/hf041-04-wind.csv year year of measurement YYYY plot plot number. One of 14 20x20m plots. plot number stem stems are numbered starting at #1 in each plot. Stem numbers for 1984 and 2015 do not match, so change over time for individual pieces is not possible. stem number species not recorded in 1984. In 2015, identity of the piece, to species of genus if possible, but sometimes listed simply as ‘conifer’, ‘deciduous’, or ‘unknown’ ACRU Acer rubrum BELE Betula lenta BEPA Betula papyrifera BETULA Betula species CONIFER conifer DECIDUOUS deciduous FAGR Fagus grandifolia PIST Pinus strobus TSCA Tsuga canadensis UNKNOWN unknown NA missing value angle the orientation of the downed trees is recorded in degrees, based on magnetic (not true) north degree 1 whole NA missing value dia1 diameter at the bottom end of the downed tree in 1984. Because of rot, this may be an approximate measurement. If the bottom end of the tree is outside of the plot, the bottom diameter is measured at the plot boundary. centimeter 0.1 real NA missing value dia2 diameter at the top end of the downed tree in 1984. Because of rot, this may be an approximate measurement. If the top end of the tree is outside of the plot, the top diameter is measured at the plot boundary. centimeter 0.1 real NA missing value length length of the downed tree within the plot, that is, if part of the downed tree is outside the plot boundary, it is not included in the measurement meter 0.1 real NA missing value cond1.3 condition of tree (recorded in 1984 and 2015) 1 solid 2 partially decayed, broken 3 decomposed into soil NA no data cond1.5 condition of tree on a 5-point decay scale (2015 only) 1 Wood intact and hard. Bark intact. Fine twigs (possibly needles/leaves) present. Cross-sectional shape is round. Tree may be elevated by supporting branches. No invading roots. 2 Wood intact and hard. Bark has begun to detach. Fine twigs and needles/leaves absent. Cross-sectional shape is round. Tree may be elevated but sagging slightly. No invading roots. 3 Wood is hard to partially soft. Some bark may remain attached. Cross-sectional shape is round. Tree may be sagging near the ground. Roots invade sapwood. 4 Wood substantially decayed and pieces easily slough off. Some bark may remain. Cross-sectional shape is elliptical. Tree on the ground. Roots invade the heartwood. 5 Wood decayed throughout. May be in many soft portions or punky and resembling organic soil. Shape elliptical to flattened. Tree is on the ground, partially sunken into the organic layer. origin origin of tree W windthrow S snap NA no data Free text (unrestricted) .* notes notes notes NA missing value 442 plot community regional long-term measurement