248 saccharum) ranked one through three in relative density, relative dominance, and IV (Table 1). Together, they composed approxi- mately 88% of the relative dominance (total basal area) of all tree species at this site. At Moist Valley, Liriodendron and Acer saccharum ranked first and second, respectively, in relative fre- quency, whereas oaks ranked third. At the moist, south-facing South Slope, Liriodendron and spe- cies of oaks ranked first and second in relative density and rela- tive dominance in 1935 and 2005. Together these species com- posed approximately 80% of the total basal area at this site. Frequency values for all tree species were low at the South Slope; Liriodendron ranked first in relative frequency followed by the oaks. At Dry Ridge, oak dominated. Five oak species, red oak (Quercus rubra), black oak (Q. velutina), chestnut oak (Q. pri- nus), white oak (Q. alba), and scarlet oak (Q. coccinea), com- posed 95% of the relative dominance at Dry Ridge in 1935 and 80.4% of the relative dominance in 2005. Oak species together composed 78% of the relative density, 69% of the relative fre- quency, and a summed IV of 242 out of a possible 300 in 1935. Density values (number per ha) for saplings, trees with dbh less than 7.6 cm (3 in), are presented in Table 2. Dry Ridge has the greatest number of saplings per hectare (7,350). Black cherry (Prunus serotina), an edge and/or successional species, was most abundant (3,500 per ha). Few P. serotina with a dbh greater than 7.6 cm (3 in) were observed at Dry Ridge; most occurred at the sunlit edge of the forest. The South Slope and Moist Valley sites had fewer saplings than Dry Ridge. White ash (Fraxinus) was most abundant at the South Slope (700 per ha) followed by hickory (Carya) (350 ha). Liriodendron, the dominant canopy species at South Slope had 150 per ha as did P. serotina. At Moist Valley, Acer saccharum ranked first in number of saplings (400 ha). Acer saccharum was the second most abun- dant large tree followed by Liriodendron. The sapling number for Liriodendron was 150 per ha. The alien white mulberry (Morus alba), Fraxinus spp., and the alien Norway maple (Acer platanoides) were represented by 350, 250, and 200 saplings, respectively. At South Slope, density and frequency data for saplings trees with a dbh less than 7.6 cm are presented in Table 2. Bitternut (Carya cordiformis) saplings were more abundant than Quercus and Liriodendron. At Dry Ridge, Prunus serotina was the most abundant sapling outnumbering Quercus rubra, the second ranked sapling, by fourfold. Dry Ridge had the greatest number of saplings/ha and the greatest diversity of tree sapling species. Quercus rubra, the dominant tree at Dry Ridge, ranked third in number of saplings per hectare, 450, as did sassafras (Sassafras albidum) (Table 2). There has been no change in the first ranked taxon at each of the three study sites over 70 years from 1935 and 2005 (Table 1). At the Moist Valley and South Slope sites, Liriodendron tulip- ifera was the dominant tree, whereas Quercus was the dominant genus at Dry Ridge. Tree of heaven (Alianthus altissima) and ginkgo (Ginkgo biloba), both nonnative species, were no longer found at Moist Valley. The ginkgo was obviously planted in the last century or earlier and probably was outshaded as the forest matured. Alianthus altissima is not shade-adapted and probably succumbed in the competition for light, although this species may have potential to invade gaps in the forest canopy (Knapp and Canham 2000). Canadian hemlock (Tsuga canadensis), ©2008 International Society of Arboriculture Stalter and Kincaid: 70-Year History of Arborescent Vegetation identified at Moist Valley in 2005, was planted by the Parks Department. At South Slope, oaks have increased in relative dominance, whereas maples (Acer spp.) and sweet birch (Betula lenta) have declined since 1935. Hickory (Carya) and American elm (Ulmus americana) have increased in relative dominance (Table 1). At Dry Ridge, oaks have dominated for the past 70 years. The relative dominance value for all oaks has decreased slightly from 95% to 80% (Table 1). At Dry Ridge, cherry (Prunus) has shown a slight decline in relative dominance but had the greatest num- ber of individuals in the (less than 7.6 cm dbh) sapling class (Table 2). Prunus serotina, an earlier successional species, does not compete well with the more shade-tolerant oaks at Dry Ridge. Early in the 20th century in northern Queens County, New York, Harper (1917) reported that Q. velutina, Q. alba, Carya spp., and American chestnut (Castanea dentata, dying) ac- counted for 41% of the trees. In Queens County, Greller (1972) identified 43 “witness trees” listed in deeds and surveyor records to delineate property lines from 1685 to 1764. Among the wit- ness trees listed were 14 black oak (33%), seven walnuts, Carya spp. (16%), six white oaks (14%), five chestnuts (12%), and 11 additional individual tree species. At Inwood Park, oaks com- prise the majority of the individuals at Dry Ridge and are Table 3. Comparison of relative density of trees in the forests of Inwood Park in the 1935 and 2005 study. Taxon 1. Quercus 1935 Census 0.331 Quercus Q. rubra Q. alba Q. prinus Q. velutina Q. coccinea 2. Liriodendron tulipifera 3. Acer 4. Cornus florida 5. Betula lenta 6. Carya cordiformis 7. Fraxinus americana 8. Prunus 9. Juglans cinera 10. Carpinus caroliniana 11. Ulmus americana 12. Catalpa spp. 13. Celtis occidentalis 16. Robinia pseudoacacia 17. Sassafras albidum 18. Morus alba 19. Tilia cordata 20. Aralia spinosa 0.214 0.136 0.084 0.065 0.032 0.026 0.026 0.019 0.013 0.013 0.006 0.006 14. Liquidambar styraciflua 0.006 15. Nyssa sylvatica 0.006 0.006 0.006 — — — 21. Aesculus hippocastanum — 22. Hamamelis virginiana — 23. Populus deltoides 24. Tsuga canadensis — — Acer 2005 Census 0.427 0.265 0.059 0.049 0.039 0.015 0.142 0.059 A. saccharum 0.054 A. rubrum Prunus P. serotina P. avium 0.005 0.025 0.029 0.044 0.029 0.108 0.103 0.005 — — 0.025 — 0.015 — — 0.005 0.039 0.015 0.010 0.010 0.005 0.005 0.005 0.005
July 2008
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