Appendix I: Establishment and management of NFT plantations

1. INTRODUCTION

The success of NFT plantings is largely dependent upon careful establishment and management in the early stages of growth in both experimental and field plantings. This is true of all types of forest plantations, but is of special importance in NFT plantation establishment due to the slow initial growth of many NFT species, and the intolerance of these species to shading.

2. PREPARATION OF PLANTING MATERIALS

Although preparation of planting materials is often one of the least expensive operations in plantation management, it is one of the most important.

A. Species selection. Serious consideration must be given to matching the environmental requirements of desired species to the planting environment. There are no "miracle trees" which grow well on all sites, yet there are generally tree species which are well adapted to all but the most extreme sites.

B. Selection of seed sources. Seed may be obtained from commercial sources or may be collected or produced locally. Forest tree seed may be rated into the following classes:

Lowest

Seed of most NFT species is available only from preference classes 3-5.

B. Seed preparation. The most important practice required to prepare seeds of many NFT species for planting is scarification. Scarification is the process used to weaken the seed coat of hard-coated seed to allow water to penetrate and hasten germination. A wide variety of scarification methods can be used, including:

1. Mechanical scarification-using nail clippers, carborundum, or commercial drum scarifiers;

2. Hot water treatment-soaking of seed in 80-100C water for short (5 min.) periods of time to soften the seed coat;

3. Chemical treatment-seed are soaked in sulphuric acid and rinsed thoroughly in water.

Scarification techniques vary with the quantity of seed to be prepared, the tools which are available, and the type of seed to be scarified. The general rule is to scarify seed so that the seed coat is weakened enough to allow water to enter, and at the same time take care to avoid damage to the cotyledon and embryo.

3. PLANTATION ESTABLISHMENT

Plantings may be established from seedlings, stem cuttings, stump cuttings, or direct seeding. Each of these types of planting must be done during periods of adequate rainfall, and must be protected from weeds and pests. Seedlings of NFT species are often slow starting, do not tolerate severe weed competition, and must be planted into well-prepared seedbeds to obtain the most rapid early growth.

Since NFT fix nitrogen in cooperation with soil-borne bacteria, it is essential that these bacteria be present in the soil for nitrogen fixation to take place. If the selected species have not been grown in the planting area, inocula containing these bacteria may need to be imported and mixed with seed prior to planting.

Since phosphorous is the most common limiting macronutrient for NFT species, fertilization with superphosphate or rock phosphate is often necessary for optimum yields. In more acid soils (e.g. less than 5.0), calcium deficiency may be a major limiting factor which can be remedied by additions of dolomite or calcium sulphate.

4. MAINTENANCE

Weed control is the most important maintenance operation. The number of weedings which must be done may vary tremendously with site qualities, quality of planting materials and previous uses of the planting site. Generally, the more hot and humid the site, and the smaller and poorer the quality of the planting stock, the greater the number of weedings which must be done.

Roguing, or removal of off-type trees is an important maintenance operation when plantings are to be used for seed collections.