EEB 337H - Families of Vascular Plants 

Ontario deciduous and mixed forests compared

Compare the tree species composition along the moisture gradient in the two forest types. The numerical entries are average importance values for species in the different moisture regimes of the two forest types (under MAX, the maximum importance value observed for a species in the forest region). Note how some species are present in one region but not the other, or occupy more or less of the moisture gradient depending on which region they are in (compare red and sugar maples, basswood, and white ash).
  Deciduous Forest           Mixed Forest
SPECIES MAX DRY DRY-MESIC MESIC WET-MESIC WET DRY DRY-MESIC MESIC WET-MESIC WET MAX
white oak 167 56 16       15 6       97
black oak 236 56                    
red cedar 287 32         24         227
white pine 99 22         60 27       228
shagbark hickory 123 17                    
red maple 135 14 19 14 10 28       12 14 56
hackberry 126 7       2            
bigtooth aspen 39 5           11       225
flowering dogwood 50 3                    
red pine             46 8       229
jack pine             45         300
red oak 151   40   13   30 18       280
pitch pine             12         93
white birch 223       13   7 16     7 90
sugar maple 227   51 98 32   6 92 183 20   289
beech 215   62 60 26     33 27     185
white ash 121   18 20 32 18   10 6     52
ironwood 45   12           7     42
black walnut 97   5   5              
hemlock 98   5             17   108
tuliptree 57   3   3              
chinquapin oak 42   3                  
white elm 187     27 59 69     12 62 80 238
basswood 64     13 14     12 17 11   55
red elm 98     11                
black cherry 55     9                
black maple 66     7                
yellow birch 50     4         12 18   83
[chesnut] 39     1                
balsam poplar 30         1     6   6 38
bitternut hickory 137       15              
burr oak 98       10              
swamp white oak 74       9              
butternut 97       5              
black ash 48       3         11 34 159
blue beech 24       2              
rock elm 24       2              
cucumber tree 24       1              
white cedar                   42 25 279
silver maple 187         41       30 66 209
aspen 296         14   8   23   152
green ash 40         5       21 24 121
black willow 216         24            
pin oak 228         16            
cottonwood 178         14            
peachleaf willow 198         11            
Manitoba maple 102         8         5 64
sycamore 87         8            
black gum 18         1            
tamarack                     13 149
black spruce                     9 25
gray birch                     9 100
balsam fir               10     7 140

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Explanation of terms:

Importance Value
Importance Value is the sum of three measures of how a species is represented in an area being sampled: (a) relative frequency, (b) relative density, and (c) relative dominance, each as a percent. The maximum possible importance value is thus 300 (e.g. jack pine, in the mixed forest, may be the only tree species present in some stands).
Frequency
This is the number of sampling points at which a species is found. Relative frequency for a given species is the proportion of the total frequencies for all species.
Density
This is based on counting how many trees of each species were found in the sampling area. Relative density is the proportion of the total number of trees sampled accounted for by a given species.
Dominance
This is a measure of tree size, and is calculated from tree diameter at breast height as the basal area of the tree. Relative dominance is the proportion of total basal area for all species accounted for by the total basal area of a given species.

Sources:

Eckenwalder, J. E. (1998). Lecture notes on Systematics and the Ontario landscape for ENV 234.

Lambert, J. D. H. & P. F. Maycock (1968). The ecology of terricolous lichens of the northern conifer-hardwood forests of central eastern Canada. Canadian Journal of Botany 46: 1043-1078.

Maycock, P. F. (1963). The phytosociology of the deciduous forests of extreme southern Ontario. Canadian Journal of Botany 41: 379-438.

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