Table 3. Summary table showing the results of model validation.

Terrestrial Biome	n	Pred. Mean	Obs. Mean	SD	Pred. Sum	Obs. Sum	SD Sum
n= number of withheld plots, ~20% of total; Pred. Mean=Predicted mean number of trees per pixel, post scaling, at locations of withheld 20% of plots; Obs. Mean=Observed mean number of trees per plot x 100, for withheld 20% of plots; s.d.=Standard deviation of pixel-level predictions at withheld 20% of plot locations; Pred. Sum=Sum of predicted number of trees per pixel at all plot locations within each biome, post scaling; Obs. Sum=Sum of observed number of trees per plot×100, for all plots within each biome; SD Sum=Standard deviation of predicted number of trees per pixel for all plot locations within each biome; % Difference=Percent difference in the total number of trees predicted (by pixel) and observed (plot×100) at all plot locations within each biome.
Boreal forests	1,116	98,157	94,459	1,168	109,542,928	105,416,204	1,303,045
Deserts	2,921	28,115	24,337	235	82,122,745	71,089,686	685,260
Flooded grasslands	55	47,691	50,576	2,894	2,623,006	2,781,658	159,169
Mangroves	—	—	—	—	—	—	—
Mediterranean forests	3,333	99,681	87,080	902	332,235,677	290,238,564	3,006,751
Montane grasslands	28	88,356	83,125	6,583	2,473,968	2,327,500	184,337
Temperate broadleaf	54,681	49,524	48,548	108	2,708,012,198	2,654,674,881	5,892,683
Temperate conifer	16,808	43,864	42,661	132	737,265,239	717,049,203	2,224,412
Temperate grasslands	3,415	30,406	28,215	264	103,835,175	96,353,092	900,426
Tropical coniferous	—	—	—	—	—	—	—
Tropical dry	17	48,525	30,938	4,083	824,925	525,938	69,415
Tropical grasslands	148	32,038	26,504	1,130	4,741,584	3,922,520	167,309
Tropical moist	1,017	80,839	77,722	795	82,212,834	79,043,004	808,476
Tundra	430	105,216	105,973	1,815	45,242,812	45,568,300	780,448
Total	83,969	752,410	700,137		4,211,133,091	4,068,990,550
% Difference						3.5%