ESTABLISHING NATIVE PLANTATIONS

Forest and Bird, Issue 55, 1 February 1940, Page 13

ESTABLISHING NATIVE PLANTATIONS

By E. V. Sanderson

SOME HELPFUL ADVICE

THE first consideration which faces anybody who is contemplating the establishment of a native plantation or bush on any particular area is the conditions of the soil, the aspect (whether coastal or inland, etc.), and the nature of the existing vegetational covering. The first need is, of course, the exclusion of alien mammals, including rabbits, hares and opossums. The very fact of the area being thus closed will straight away cause a modification of the vegetation in the enclosure. Exactly what will happen can usually be judged fairly well by observation on adjacent closed areas.

A Grass-covered Area. Suppose, first of all, that the chosen area is pasture land. As a close sward of grass, with the accompanying compressed soil, is inimical to the growth of trees, the first need will be the destruction of the turf either by ploughing it in, or merely grubbing it during dry weather.

The next undertaking will be the planting of the desired species of trees. The choosing of these should be limited to those which are native to the district. The suitability of each species should be carefully considered for its individual position. A study of the conditions where a plant has successfully established itself naturally will be helpful in deciding this matter.

Plants obtained from a reliable nurseryman are to be preferred; but, if they are collected, then only small plantssay, two or three inches in height— be chosen from those that may be found struggling for sustenance on some roadside bank or similar hard situation.

The plants should be carefully removed, care being taken to keep the roots damp. They should not be exposed to the sun or any drying conditions, and they should be promptly planted. Ninety per cent, of plants removed from the snug bush conditions die unless they are cared for by experts.

The holes in which the seedlings are to be planted should be dug some time before planting. The filling should include such plant food as rotten turf, decayed wood and other decaying humus. Time and care in the preparation prior to planting will save much future labour

and expedite the growth of the plants in quite an extraordinary manner. The best procedure of all, however, is to grow one’s own plants from seed or from a few handfuls of the humus underneath the desired trees. Place the seed or humus matter (which will contain much seed) in a box of humus and soil or sawdust and soil. Keep the box in those semi-shaded conditions similar to those which exist in the bush where trees have been destroyed by storm or otherwise. The contents of the box should be kept moist until the seeds germinate. Kowhai, for instance, takes at least six weeksoften longer. Then prick the seedlings out and place each one individually into a large pot or even a tin, with a wide hole cut in the bottom and covered internally by a piece of wood or other material.

The best times for planting are immediately the autumn rains begin or in the early days of spring. Puddle the plants in and then compress the soil very firmly with your boots. People with big feet and heavy boots make good planters.

Planting is a severe operation which has been performed on the young trees, and they will therefore need care and attention for the following two or three weeks.

The trees which are first of all planted are to be those which will eventually form the bush or plantation. Therefore they must be spaced sufficiently far apart to permit reasonable future crown development. For instance, a Pohutakawa (Metrosideros tomentosa) will cover a circle about 20 feet in diameter; a Hinau (Elaecocarpus dentatus) will similarly cover a circle 30 feet in diameter; a Kowhai (Edwardsia microphylla) a circle about 15 feet in diameter.

The next process is to fill in the large intervening spaces with some rapid-growing plant, preferably of a nitrogenous nature. With the aid of nurse plants the plantation comes up en masse, one plant sheltering and shielding the other and at the same time quickly doing away with the necessity of further grubbing of grass. Light-growing weeds such as chickweed and nightshade do not matter, as they can be re-

garded as beneficial in that they provide some additional humus matter, protect the surface of the soil and conserve moisture.

Digging with a spade should be avoided because most of the native trees are very superficially rooted.

Nurse plants may consist of such species as common broom, tree lucerne, lacebark, rangiora, or mahoe. Some valuable recent research work conducted by an Otago botanist has proved that mahoe is a very fine soil-improver and a counteractant of acid conditions. The addition of this tree is likely to prove very beneficial in the plantation. The first year calls for the most work. Grass which tries to re-assert itself should receive constant attention; drying winds may cause a need to water, and other difficulties occur.

In the second year the nurse plants begin to be helpful. In the third year establishment will usually be assured and a minimum of effort will be required.

After that the nurse plants will become more or less over-competitive to some of the trees required as permanents. A judicious cutting back and finally cutting out of nurse plants will then be the procedure for some years. However, it is always advisable to rather underdo than overdo these operations at all times; otherwise grass will again become a hindrance to other growths.

A Simpler Method on Grasslands. Similar results to the foregoing can be obtained in a manner by following nature’s way. In the preceding comments nature’s methods are expedited, but they are more or less reversed in that the permanents and the “nurses” are planted at the same time. This simpler, but rather slower, method is to fence out all mammals, then plant the area with tree-lucerne

(tegasaste), spacing these 12 feet apart. They will grow amongst grass and almost anywhere, except where salty winds are frequent. In three years they will overcome and eradicate the grass and torm a beautiful seed bed. Now broadcast seed. Those seeds will germinate which are likely to establish trees. Underlop the lucerne trees when necessary, leaving all litter on the ground; in fact, a good maxim for all efforts to establish native plantations is: “never tidy up.” Finally the lucernes are cut out, and an overdense population of natives remains. Thin them out as necessity requires, or leave it to nature. She will do it. When an Area is Already Plant-covered.

The area which it is desired to convert into bush may, however, have considerable plant growth on it such as titree, tauhinu, broom, tern, tutu and other natives like rangiora. This condition is only too often dubbed as rubbishcovered, which is quite a wrong conception of the position. That mistaken notion comes from the fact that the land is unsuitable as it stands for grazing purposes. As a matter of fact it is in that state which is nature’s initial attempt to re-establish her forest; if fire and mammals were totally excluded, she would succeed.

The so-called rubbish consists of the necessary initial nurse plants. Where these conditions exist the aim should be to help nature by planting suitable trees in small cleared pockets. Horticulturists, usually imbued with the “tidy garden” idea, are often guilty of clearing an area in the so-called rubbish stage and then planting. Much unnecessary work follows as a natural sequence; the growth of the trees is much retarded. Indeed, as the writer has frequently seen, grass becomes dominant, and total failure results.