Reproductive Ecology of Male and Female Strobili and Mating System in Two Different Populations of Pinus roxburghii

Table 4

Temporal and spatial variation in frequency of air borne pollen in P. roxburghii.

Observed variables	Lower altitude (900 m asl)				Higher altitude (1900 m asl)
	1998	1999	2000	2001	1998	1999	2000	2001
Pollen concentrations in the air between 1200 and 1600 h of the day (pollen/cm^2)	119±9.84	160±12.19	140±8.34	180±10.14	98±4.34	215±18.79	142±9.12	186±16.34
Pollen deposition per scale-bract complex in the ovulate cone between 1200 and 1600 h of the day (pollen/bract scale)	17±1.16	36±4.73	26±2.12	32±6.16	22±2.57	29±5.12	42±2.84	52±8.12