Environment and tree size controlling stem sap flux in a perhumid tropical forest of Central Sulawesi, Indonesia

Table 1 Biometric characteristics of the seven common tree species investigated for sap flux in Pono Valley, Central Sulawesi

Species	Family	n	DBH (cm)	H (m)	SA (cm²)	J₂₀₀₇ (g cm⁻² h⁻¹)	J₂₀₀₈ (g cm⁻² h⁻¹)
V. arborea Buch.-Ham.	Asteraceae	3	20.1–43.0	22.0–28.7	73.6–256.9	1.55 ± 0.64	1.93 ± 0.73
S. apiculata A.W. Benn.	Burseraceae	5	14.6–58.2	17.4–27.6	54.5–589.3	1.74 ± 0.29	1.43 ± 0.80
P. luzoniense (Fern.-Vill.) Vidal	Sapotaceae	6	10.4–95.0	17.6–44.7	43.3–4394.9	2.04 ± 1.23	2.15 ± 1.28
C. laevigata Blume	Lauraceae	6	11.2–27.9	15.4–33.2	45.2–112.7	1.55 ± 0.41	1.46 ± 0.83
P. firma (Miq.) Baehni	Sapotaceae	5	14.7–27.9	14.7–44.3	54.8–745.2	3.05 ± 1.23	2.68 ± 1.49
P. excelsa Bl. var. borneensis (Heine) Sleum.	Icacinaceae	6	11.7–45.7	12.3–24.7	46.5–297.8	2.37 ± 1.23	2.09 ± 1.18
C. acuminatissima (Blume) Rheder	Fagaceae	8	11.8–71.4	17.6–43.9	46.8–1211.5	4.08 ± 1.45	4.70 ± 1.84

Stem diameter at breast height (DBH), total tree height (H), sapwood area (SA) as estimated from dye injection experiments and the SA–DBH relationship in the species. J is the mean xylem flux density ± SD measured in 2007 (May to December) and 2008 (January to December) in the outer 2 cm of the active xylem by means of the constant heating method after Granier (1985). The number of replicates (n) is the number of trees monitored for xylem sap flux density

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