Abstract
During 1951 and 1952 the position and diameter were recorded for each tree on a 140 ? 140 m plot of immature climax oakhickory forest in the Duke Forest, Durham, North Carolina. To ascertain the changes in structure associated with climax forest maturation, this plot was remapped in 1974 and the two maps compared. In general, tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974. The most notable changes were a 75% reduction in density of Carya spp. and a 230% increase in density of Acer rubrum. Many dominant species showed significant reduction of numbers in smaller size classes in 1974. Tree-by-tree analysis of mortality and recruitment revealed low rates of population recruitment and high mortality rates in these smaller size classes. Tree pattern, analyzed by quadrat and point-to-neighbor methods, was clumped in smaller size classes and random or regular in larger size classes on both maps. However, total tree pattern shifted from random in 1951-52 to regular in 1974. This shift was the result of significantly higher mortality in the smaller size classes which had clumped distributions. Species diversity, H', decreased during this time; however, pattern diversity (Pielou, 1966) increased. Decreased species diversity resulted from diminished equitability, whereas increased pattern diversity was probably due to shifts in tree pattern.
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Claims 13
Claim · model-written summary
Tree density decreased over the study period, especially in overstory trees.
Verbatim
e0“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
t0“Forest”
Claim · model-written summary
Total basal area increased from 1951-52 to 1974.
Verbatim
e0“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
t0“Forest”
Claim · model-written summary
Carya spp. density fell 75 percent.
CaryaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 75% reduction in density of Carya spp.”
Claim · model-written summary
Acer rubrum density rose 230 percent.
- Taxon
- Acer rubrum
Acer rubrume0 - Outcome
- densitye0
- Direction
- increasee0
- Value
- 230%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 230% increase in density of Acer rubrum”
Claim · model-written summary
Many dominant species had significantly fewer individuals in smaller size classes in 1974.
Verbatim
e0“Many dominant species showed significant reduction of numbers in smaller size classes in 1974”
Claim · model-written summary
Smaller size classes had low recruitment and high mortality.
Verbatim
e0“low rates of population recruitment and high mortality rates in these smaller size classes”
t0“Forest”
e1“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
Claim · model-written summary
Small trees were clumped and larger trees random or regular on both maps.
Verbatim
e0“Tree pattern, analyzed by quadrat and point-to-neighbor methods, was clumped in smaller size classes and random or regular in larger size classes on both maps”
Claim · model-written summary
Overall tree pattern shifted from random to regular by 1974.
Verbatim
e0“total tree pattern shifted from random in 1951-52 to regular in 1974”
Claim · model-written summary
Higher mortality among clumped small trees explained the pattern shift.
Verbatim
e0“This shift was the result of significantly higher mortality in the smaller size classes which had clumped distributions”
t0“Forest”
e1“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
Claim · model-written summary
Species diversity decreased.
Verbatim
e0“Species diversity, H', decreased during this time”
t0“Forest”
e1“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
Claim · model-written summary
Pattern diversity increased.
Verbatim
e0“pattern diversity (Pielou, 1966) increased”
t0“Forest”
e1“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
Claim · model-written summary
Reduced equitability explained lower species diversity.
Verbatim
e0“Decreased species diversity resulted from diminished equitability”
t0“Forest”
e1“tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974”
Claim · model-written summary
Shifts in tree pattern probably explained increased pattern diversity.
Verbatim
e0“increased pattern diversity was probably due to shifts in tree pattern”
t0“Forest”