10 
Although the pine type is reverting to hardwood, the in- 
coming stands are not in themselves final. It would appear 
that mature hardwood stands do not provide such a good 
seed bed for their own seed as do the pine stands, and hence 
the advance growth under hardwoods is not so dense. This 
probably makes possible the reintroduction of the pine. The 
climax forest of the region is one of mixed pine and hard- 
woods with an understory of many species for the better 
sites. 
The question of the yield of unmanaged second growth 
hardwood stands has been fully considered and the results 
are given in Harvard Forest Bulletin No. 2, ‘‘Growth Study 
and Normal Yield Tables for Second Growth Hardwood 
Stands in Central New England,” by J. Nelson Spaeth. 
Since in these stands, arising from the cutting of both pine 
and hardwood, the most valuable trees are oak and ash and, 
also, since a great percentage of the young growth consists of 
these two trees, it is obvious that the forest of the next rota- 
tion will be largely an oak-ash stand. This type is now fully 
recognized by the silvicultural policy on the Harvard Forest, 
partly because of the great value of these two species and 
partly because of the prohibitive cost of reconstituting pine 
stands on the better soils. As these forests are situated in a 
region of wood-using industries where practically every load 
of lumber can be sold, as well as cordwood, they can be 
placed under intensive management. This has already been 
begun on the Harvard Forest, and the purpose of the present 
study was to obtain data for the purposes of future manage- 
ment. The specific questions for determination were, there- 
fore, rotation and density as related to growth, tree form, 
and value of yield. 
