Spodsol in clay loam, under full hardwood (maple etc.) at Camp #2 of J.D. Irving at Black Brook. N.B. disturbed Ae on right most likely from windthrow.

View of branch of deficient white pine. Treated in May with K fertilizer, photo in October. N.B. size and colour of current vs. last year's foliage.

Red pine plantation 35 years old treated with K at 200lb/ac. at age 20cf. with #283 and note much less light of forest floor due to denser foliage.

Untreated red pine plantation, 35 years old, planted at 1.5x1.5m at Warrensburg.

Red pine 30 years old at Warrensburg, left is untreated control; right was treated with K at 200lb/ac when stand was 15 years old.

Dr. Howard Lowenstein in Heinberg's 25 year old red pine in which in 1935 Heiberg dug in 2 inches on humus into the soil before planting.

Dr. H. Lowenstein in 25 year old red pine of Heiberg's trial. This is the humus series control plot at Warrensburg.

View of white spruce plantations at Warrensburg; background fertilized with K at 200lb/ac. foreground untreated.

Red pine plantation root deep in C horizon in old root channel cf. with root slides.

Hinckley Series sandy loam in outwash. Typical profile at Pack Forest, site of Heiberg's trials.