Dr. Harrington's Informal Notes Prepared for Capital Ideas - Live! August 21, 2002
Cost-effective TSI treatments to consider:
1. For young pine plantations (less than 5 years old)
a. Pre-commercial thinning: cut all hardwoods and poorly formed pines (rust, forked, leaning) to leave crop pine trees spaced at 10-12' between trees. Most plantations in cutovers tend to be overstocked with excess hardwood and pine stems, so for this stage of stand development this treatment probably has the greatest overall payoff of any treatment.
b. Competition release: Arsenal+Escort (16+1 oz/acre); excellent treatment for releasing pines from overtopping sweetgum, oak, blackberry, sumac; saves plantation from significant mortality that results from overtopping. Also, consider injection or basal herbicide application for removal of individual stems.
c. Fertilization with P in the Coastal Plain is another good treatment to consider; do not combine with N since this will intensify competition from associated vegetation.
2. For mid-rotation (10-15 years old) pine stands
a. Thinning from below to remove subordinate and lower quality pine and hardwood stems, leaving crop trees at a 14' spacing. Leave better hardwoods where no pine stocking exists. Given the poor pulpwood market and low availability of thinning contractors, it still makes good economic sense to thin an overstocked stand at a break-even or even a cost basis. This is because the potential response of the stand to density management can be excellent.
b. Competition release as described above for young stands; may only be cost effective if hardwood density exceeds 5 ft2/acre or 1000 stems/acre.
c. Stands with uniform and moderate pine stocking and minimal hardwood/shrub competition (such as those planted in retired agricultural fields) are excellent candidates for fertilization. However, keep in mind that it is not logical to fertilize overstocked stands that are choked with hardwood competition because very little of the nutrient amendment will get absorbed by the crop pines. The most common fertilizer treatment is 200 lbs. of elemental N per acre, applied as urea, which is 46% N. Addition of P to the N treatment makes sense (usually at a rate of 50 lbs. element per acre), but often requires a second treatment (with associated application costs) because no fertilizer compound exists that incorporates N and P at a 4:1 ratio.
3. For natural, mixed stands of hardwoods and pines
Thinning from below to provide plenty of growing space for crop pines (14' spacing) and somewhat less space for hardwoods (10-12' spacing). This approach allows pines to develop into more valuable saw logs while allowing much of the rest of the stand to grow pulpwood in hardwoods. Once again, it should be stressed that density management at the proper time (while trees have large crowns...40% of their height or more) can be the most cost effective treatment in terms of growth response and future value of individual stems. The treatment shifts production from the condition of too many stems to a condition of much fewer high quality stems.