MEASURE OF TOLERANCE. 
TuURSKY (1904: 32). 
Abies pectinata (silver fir). 
Fagus (beech). 
Picea (Norway spruce). 
Carpinus betulus (European horn- 
beam). 
Ulmus montana (wych elm). 
Pinus laricio, var. austriaca (Austrian 
pine). 
Alnus glutinosa (black alder). 
Fraxinus excelsior (Kuropean ash). 
Quercus (oak). 
Populus (poplar). 
Pinus sylwestris (Seotch pine). 
Betula (birch). 
Larixs europea (larch). 
21 
WARMING (1909: 18). 
Abies pectinata (silver fir). 
Fagus (beech). 
Carpinus  betulus 
beam). 
Tilia (basswood). 
Picea (Norway spruce). 
Pinus montana (Swiss pine). 
Acer pseudoplatanus (sycamore maple). 
Ulmus effusa (spreading elm). 
Quercus (oak). 
Fraxinus excelsior (Kuropean ash). 
Pinus strobus (white pine). 
Pinus sylwestris (Scotch pine). 
Alnus incana (hoary alder). 
Populus tremula (aspen-poplar). 
Betula (birch). 
Larig europea (Huropean larch). 
(European  horn- 
The following are scales of tolerance prepared for some of our 
American trees: 
WESTERN SPECIES. 
VERY TOLERANT. 
Tasus brevifolia (western yew). 
Picea engelmanni (Engelmann spruce). 
Abies lasiocarpa (alpine fir). 
Abies concolor (white fir). 
Thuja plicata (western red cedar). 
Tsuga heterophylla (western hem- 
lock). 
Tsuga mertensiana (mountain hem- 
lock). 
Picea sitchensis (Sitka spruce). 
TOLERANT. 
Chamecyparis lawsoniana (Port Or- 
ford cedar). 
Libocedrus decurrens (incense cedar). 
Picea parryana (blue spruce). 
Sequoia sempervirens (redwood). 
INTOLERANT. 
Abies magnifica (red fir). 
Pinus ponderosa (western 
pine). 
Pinus jeffreyi (Jeffrey pine). 
Pinus lambertiana (sugar pine). 
Pinus aristata (bristle-cone pine). 
yellow 
VERY INTOLERANT. 
Larixv tyallii (alpine larch). 
Larix occidentalis (western larch). 
Pinus albicaulis (white-bark pine). 
Pinus attenuata (knobecone pine). 
Pinus balfouriana (foxtail pine). 
Pinus coulteri (Coulter pine). 
Pinus flexilis (limber pine). 
Pinus monophylla (single-leaf pine). 
Pinus edulis (pifion). 
Pinus sabiniana (digger pine). 
Pinus contorta (lodgepole pine). 
