Table 2 - Productivity Gains for Silvicultural Practices for Southern Pine Plantations

Productivity gains for silvicultural practices for Southern pine plantations, their relative costs, time needed to gain benefit and energy output to energy input ration.

Operational class	Typical response %	Number of rotations to harvest gain	Relative cost	Energy output:input ratio (% productivity gain used)a
Usually long-term responses
Tree breeding	10 to 50	b2-3; ongoing	Very high	N.A.
Correct major deficiences at establishment (e.g. P)	10 to 50	1	Mod. to high	94 (38)
Improve rooting volume (e.g. rip and/or bed)	10 to 75	1	Often high	494 (60)
Usually short-term responses
Improve planting stock and planting	<10	1	Moderate	N.A.
Tillage	<10	1	High	13/37d (4)
Alter stocking level and rotation length	10 to 25	<1	Moderate	N.A.
Weed control	<10 to 50	1	Moderate	42/75d (8)
Starter Fertilizerc	<10	1	Low to mod.	14 (4)
Thinning potential mortality	<10 to 25	<1	Mod. to high	N.A.
N fertilzer mid-rotation	<10 - 25	<.5	High	10 (11)

^a From Mead and Pimentel (2006) for P. taeda on a 24-year rotation. See article for details and assumptions.

^b Improved trees are already availabe for many Southern pines so the delay will not apply. The very high costs are associated with research, but they will not be so great for the forest owner buying impoved genetic material.

^c Small application to assist establishment, e.g. 3 oz. diammonium phosphate per tree.

^d Figures dependent on methods used.

N.A. Not available from Mead and Pimentel (2006)

Based on Mead 2005a; Mead 2005b; Mead and Pimentel 2006; Stanturf and others 2003