1918] HUTCHINSON—FOREST TREES 481 
Picea mariana 
Picea canadensis 
Pinus Banksiana 
Abies balsamea 
Populus balsamifera 
Betula papyrifera 
Thuja occidentalis 
Tsuga canadensis 
Pinus Strobus 
Acer saccharum 
| Fagus americana 
| Quercus rubra 
Carya amara 
Castanea dentata 
Juglans cinerea 
Fic. 3.—Forest trees: specific ranges of tolerance with respect to temperature 
