170 College of Forestry 
(c) It is densely populated by living organisms — nota- 
bly fungi and bacteria — whose activity — especially of the 
bacteria — reduces the potential energy of dead organic stuff 
to productive energy (soluble nitrogen, etc.) and thus renders 
a fundamental service to the forest community both as to the 
food supply and by removing the menace of accumulating 
dead organisms. 
(f) It is, therefore, rich in available soil nutrients. 
(¢) It is a sanitary soil in respect to being a “ healthy ” 
environment for bacteria, forest-soil fungi and for the roots 
and other imbedded living parts of higher plants. 
(2) As to growth forms: 
The climax forest is composed of a more highly differen- 
tiated association of adaptation forms or growth forms than 
any other plant society in our area. Without attempting to 
reduce these to a technical classification* we may list as some- 
what on a previous page such “ working units” as broad- 
leaved deciduous tree, evergreen needle-leaved tree, shrub 
types, plants with perennial woody roots and annual stems, 
forms of various degrees of stem-support requirement 
(sprawlers, climbers, twiners, ete.) ; monocotyledonous and 
dicotyledonous annuals, and perennial or renascent herbs 
(by bulbs, corms, rootstocks, rhizomes, etc.; here the great 
bulk of “spring wild flowers’) ; various ferns perennial by 
root stocks or elongated rhizomes ; club-mosses, notably Lyco- 
podium luctidulum. We may regard as growth forms in this 
connection mosses of erect and creeping habit, leafy and 
thalloid liverworts, the different types of lichens (crustose, 
foliose, fruticose) and fungi, at least so far as concerns the 
fruiting bodies —mushrooms and other fleshy fungi and 
woody fungi (bracket forming, etc.). 
(3) As to growth relations: 
The diverse relations which different growth forms occupy 
in the complex forest society is right impressive. We have to 
1 Taylor, Norman. The growth forms of the flora of New York and 
Vicinity. Amer. Jour, Bot. 2:23-31, January, 1915. Further refer- 
ences to the literature on growth forms may be found in this citation. 
