Inconsistent Growth Response to Fertilization and Thinning of Lodgepole Pine in the Rocky Mountain Foothills Is Linked to Site Index

Figure 5

Diameter growth differential of thinning and fertilization treatments relative to site index of the control stands. The response variable, diameter growth differential, is the difference between DBH growth after three years of the treated stand and DBH growth of the associated control stand. White dots represent unthinned plots and black dots represent thinned plots. (a) Thin only, 𝑃=0.032, 𝑟²=0.254, (b) N-only, 𝑃=0.020, 𝑟²=0.303, N-only + thinning, 𝑃=0.003, 𝑟²=0.469, and (c) complete fertilization, 𝑃=0.334, complete + thinning, 𝑃=0.110.

(a) Thin only

(b) N-only fertilization

(c) Complete fertilization