Figure 4
From: Evaluating Douglas-fir and western hemlock volume growth in response to thinning and fertilisation
Effect of the fertilisation × thinning interaction on volume for Douglas-fir (a) and western hemlock (b). Volume trajectories are shown for thinning (35% removal) and fertilisation (450 kg/ha) treatments applied at age 30 for low (site index = 21 for Douglas-fir, site index = 25 for western hemlock), medium (site index = 29 for both species), and high (site index = 37 for Douglas-fir, site index = 33 for western hemlock) sites, with and without the interaction term. Low, with interaction: 
; medium, with interaction: 
; high, with interaction: 
; low, w/o interaction: 
; medium, w/o interaction: 
; high, w/o interaction: 
.