VOL. Il.] Forms of Trees. 5. 
Pinaster), Lebanon cedar, and the hundreds, if not thousands, of 
other evergreen trees which inhabit regions below the regular snow 
line. 4 
Nature thus eliminates from snow-visited forests all evergreen 
trees which are not suited to resist the pressure of the snow. On 
the contrary, the snowfall makes it possible for all those trees to 
live and survive which, through their outward form, are able to easily. 
shed the accumulated snow. As regards deciduous trees, no such 
upright trunks and sloping branches are necessary, as the bare limbs 
do not accumulate the snow, nor suffer under pressure. If the 
above is true, the forests of snow-visited districts will be found to 
consist of only such varieties of trees as possess the requisite form, 
that is, evergreen trees with upright, undivided trunks and down- 
ward sloping branches, as well as of deciduous trees of various not 
especially characteristic forms. Upon examination this will also be 
found to be the case. i 
A visit to the high pine forests of Sierra Nevada shows us just 
such forests. Nowhere is the snowfall heavier and nowhere is the 
characteristic form of the evergreen trees more pronounced. This 
is also the case in all other show-visited regions where forests are at 
all able to exist. Where the sndwfall is the heaviest and lasts the 
longest, all evergreen trees, at least during a certain period of their 
life, possess the required pyramidal form. Evergreen trees of any 
other form would in their struggle for existence have little or no 
chance to compete with better equipped neighbors. It follows, 
also, that the less the snowfall the less characteristic will prove the 
pyramidal form in all evergreen species, while lower down the 
‘mountains on the warmer slopes the pyramidal form may be ex- 
pected to be entirely absent. 
To refer to our nearest high mountains, the Sierra Nevada, we 
find thus on the snow-belt such trees as Adies Douglasii, Picea ama- 
bilis, Pinus Lambertiana, Libocedrus decurrens, Sequoia gigantea, 
etc. All these show in a characteristic way the pyramidal form, the 
snow-shedding branches and the undivided trunk. We find in this 
region no large live oaks, nor any large evergreen trees of globular 
or goblet shape. But in the region immediately below the heavy 
snow belt, the characteristic pyramidal shape is entirely absent. 
The forms of the evergreen trees are here evidently regulated by 
other agencies. In this region we meet with several evergreen 
