Fig. 
ONomorh wd 
LELUSa AP TONS: 
. (Overhead, side; and reflected Nehts2.22- 22246-22=. 5 Se ee ee 
. Variation in light requirement with increase in latitude and altitude. - 
. Results of experiments with shading seedlings.-.............-------- 
. Cross section: of ‘a beech leat. 203.2352 22. see aoe ee ee 
. _Cross'section of a spruce needle. 2222-222. 222 eee ee eee 
. Wiesner’s photometer Gnsolator)= 220s Oe Ss esa. eee eee 
> Glements’ photometer... Ysecca5en 5 es eee oo eee eee 
. Maximum and minimum licht intensities within crowns of trees with 
different arrancement, of toliasespacce =. ae 5 eae See ee eee 
. Hourly light intensities within the crown of ailanthus (Adlanthus glan- 
dulosa); horizontal arrangement of leaves: 2.52.2. 2222e2-2 soso 
. Hourly light intensities within the crown of black locust (Robinia 
pseudacacia); vertical arrangement of leaves. .......-.-.-.-------- 
4 
