Evaluation of different approaches to individual tree growth and survival modelling using data collected at irregular intervals – a case study for Pinus patula in Kenya

Forest Ecosystems

Table 8 Statistics for the fixed-effects models (best in boldface, worst in italics )

	Modelling and simulation approach
	Regression 1	Regression 2	Regression 2	Optimization
	1-year step	1-year step	true step	1-year step
Basal area
- bias (m² · ha^–1)	1.74	10.04	9.24	–0.28
- RMSE (m² · ha^–1)	4.24	22.73	20.49	2.73
Number of trees per hectare
- bias	–23.92	49.74	49.74	0.39
- RMSE	76.21	135.94	135.94	46.75
Annual basal area increment
- bias (m² · ha^–1)	0.579	1.611	1.497	–0.005
- bias (%)	43.21	120.22	111.71	–0.37
- RMSE (m² · ha^–1)	1.251	3.175	2.971	0.868