The principal raw material yielded by trees is wood, which can he used in many ways and for many purposes and which, along with coal - the product of trees of earlier geological periods - made possible the smelting of ores and the development of all branches of industry.

In some trees it equals two to three centimetres in a favourable year. Of the European trees great thickness is attained by the plane, chestnut, oak, lime and sycamore, and of the conifers by the fir and to somewhat lesser degree by the spruce. The “big trees” The attainable thickness of the trunk goes naturally hand in hand with the tree’s attainable age.

In the mild climate of central and western Europe, the annual increment per hectare, depending on the site, type of soil and prevailing species, averages from three to ten cubic metres of wood that can be cut without decreasing the supply and production of further wood. With systematic care and fertilization this increment can be increased even further, as is shown by the plantations of cultivated hybrid poplars with an annual increment of fifteen to twenty- live cubic metres of merchantable wood.

In the normal course of events, one would be inclined to say that an old veteran of 22 years owes you nothing, and that a bush that has been allowed to get into this senile state would be better scrapped to make space for a new start.

There is a body of opinion that says that when a rose dies, another will not grow in its place because it knows and dies in sympathy! You may think it just as crackers as the folk who have a chat with their plants, but the fact is that it happens, and a lot of gardeners write letters about it. The problem does cause concern, and it is widespread. No pest or disease is discernible, and yet perfectly healthy plants languish and die.

Most gardeners from this school of thought - invariably they are amateurs - point to personal experience, often repeated (an important clue).

The Austrian pine is a native of the Mediterranean countries, Spain, Calabria, Corsica, Balkan Peninsula and Asia Minor. The natural northernmost limit of its distribution was originally Austria, but today the Corsican and Austrian varieties especially are widely cultivated for their rapid growth, and high quality wood, in western and central Europe.

The tree attains a height of 40 metres and has a straight bole which, however, tends to be very knotty. It differs from the Scots pine in being more darkly coloured, with black-brown, furrowed bark extending to the dense crown with dark green foliage. The cones mature in the second year.

The jack pine is widespread in Canada and the north-eastern United States, where it grows chiefly on poorer, sandy soils. It was introduced into Europe in 1785. In the late nineteenth century it was widely planted as a forest tree because of its resistance to fungus diseases, and its rapid growth in youth. However, it was found that after the fortieth year the rate of growth declined rapidly and the bole became crooked; so the initial enthusiasm soon waned.

Pears are a favorite of home gardeners because they are attractive, suited to small spaces and indeed grow best on a lawn.

Peach and nectarine trees grow best in soil with a pH of 6.0 to 7.0. For fruit within two or three years, buy two-year-old 3- to 5-foot trees. Plant them in early spring on an elevated or sloping site to prevent flower buds from being killed by spring frosts. Cut the trees back to 21/2 to 3 feet above the ground at the time of planting.

Prune trees as little as possible after the skeleton branches have been established. It is important that pear trees carry only as much fruit as they can support. Part of the problem of overproduction will be taken care of naturally, as some of the young fruit will drop about six weeks after the flowers bloom. Thin out the remaining fruit, saving the best of each cluster, so that pears are about 6 to 8 inches apart. In many gardens pear trees do not need fertilizer; if the foliage, however, is pale or yellowish green, use 1 pound of 10-10-10 fertilizer per year of the tree’s age, scattering it under the spread of the branches. Pears should not be mulched but should be grown on a lawn area where they must compete for food and moisture with grass. The chief reason for deliberately undernourishing pear trees is to forestall damage by a bacterial infection called fire blight that attacks trees that are growing too luxuriantly.

Trees are divided roughly into three groups according to their rate of growth - fast, moderate and slow-growing.

The first group is distinguished by fast growth in the first years with culmination point at an early age, after which the rate markedly decreases. The tree usually has a short life. Fast-growing trees, therefore, do not attain great heights; on the contrary, these are attained by the moderate and slow-growing over a greater period of time, and reaches its peak at a more advanced age; the downward curve is more protracted and the tree has a longer life span (fir, spruce, beech).

The tallest and largest trees are the sequoias of North America (Sequoiadendron giganteum Buchh. and Sequoia sempervirens Endl.), the latter attaining heights of up to 112 metres or more. Heights of 80 to 90 metres are reached by some other west American conifers, e.g. the giant fir, noble fir, Douglas fir and sugar pine. Of the European trees the tallest is the European silver fir with a height of over 62 metres and the Norway spruce, which also attains a height of over 60 metres.

Every plant on Earth occurs in a certain region that can be marked out on a map. This region is termed its area of natural distribution. Knowledge of these areas is of great importance, because the woody plant grows for hundreds, and even thousands, of years in the given area, and is adapted to the climatic conditions of the locality, thus making it possible to determine whether it prefers a coastal or inland, lowland or alpine climate. The study of other data reveals what temperatures it is able to withstand in winter, as well as its soil and moisture requirements.

The white ash reaches a height of 30 to 40 metres and the bark is more coarsely furrowed than that of the common ash. It also differs from the latter in having brown buds. The odd-pinnate leaves are composed of broader, ovate leaflets and the seeds are narrowly lanceolate, about one-half narrower than the tongue-shaped wings. The seed, unlike that of the common ash, germinates in the spring of the following year. As it grows no faster than the common ash and its wood is of poorer quality it is not cultivated in European forests, though it has some value as an ornamental specimen tree in parks and avenues, especially on the poorer soils.

The root system is greatly influenced and modified by the environment. In shallow soils over rock, heavy clay soils, or on sites with a high level of underground water, even species whose roots normally penetrate to great depths may have shallow anchorage.

Conversely, in humus-rich sandy soils the roots of woody plants which normally spread out may penetrate to greater depths. Roots anchor the tree in the ground, absorb water and the mineral elements dissolved in it, and serve as storage for reserve food supplies. The structure of the roots is very similar to that of the trunk, only somewhat simpler.

Water from the soil is absorbed through the root hairs, which are filamentous outgrowths near the tip of each rootlet. The movement of water in the trunk is governed both by the osmotic function of the roots and by the rate of transpiration in the leaves.

Roots aerate the soil and promote the disintegration of the rock substrata. In this they are aided by the carbon dioxide they eliminate as well as by certain chemical substances which break up mineral particles. The nutriments in the soil arc also made available by various bacteria and fungi growing in association with the roots. Nitrogen-fixing bacteria that increase the nitrogen content of the soil live in nodules attached to the roots of the alder, black locust, honey locust and other woody plants of the pea family (Leguminosae).

The main problem why some homeowners are having second thoughts of building a sunroom is that the construction sometimes takes a lot of fuss. So many things should be monitored and be taken into consideration before you can enjoy your very own sunroom. But worry no more as do-it-yourself sunroom kits can put a big grin on your face. You no longer have to worry in hiring the best sunroom builder in town as you can do it on your own. Finding a DIY sunroom kit is no longer a task as the market now offers a huge array of DIY sunroom kits. The kit is usually comprised of all the needed materials in putting up a sunroom. Another advantage of opting for a do-it-yourself sunroom kit is that you can significantly save money. You no longer have to hire a sunroom builder just to put the room together as you can easily do it on your own. And depending on the type of sunroom kit you choose, you can also save money in the near future when it comes to energy and maintenance costs.

High up in the mountains, trees and dwarf pine hold back build-ups of snow, thus preventing the formation of the avalanches, that are a common occurrence on treeless slopes when there is a thaw, leaving devastation in their wake and often taking their toll in human lives as well.

Trees in the landscape are pleasing to the eyc and an important ornamental element, as one realizes only too well when travelling mile after mile through flat countryside with only the horizon in sight. Trees brighten the landscape and give it its individual character. The broad valleys of large rivers are hard to envisage without groves of poplars amidst the spreading meadows, or without tree-shaded pools.

In hill accustomed to see oaks, limes and maples beside farmhouses ncl churches, and in mountain pastures the occasional mountain ash, juniper and spruce. Beside mountain cottages one may see spreading sycamores, ashes, elms and beeches. Avenues alongside roads and highways not only help these to blend well with the landscape but also provide welcome shade to both man and beast.

The smooth-leaved elm is a more warmth-loving species than the wych elm and is found in Europe only as far north as the Baltic Sea. It grows mainly in the lowlands on alluvial deposits in mixed woods, together with oak, alder and poplar. It reaches a height of 30 metres, and may attain an age of several hundred years, growing a thick trunk. The globular flower buds can alr,ady be distinguished in winter.

It grows to an age of 600 to 800 years and, in the open, develops a huge trunk and broad crown. Under ideal conditions, heights of 40 metres can be attained: Up to about 20 to 30 years of age the bark is smooth and grey, in older trees it tends to become blackish-grey and deeply furrowed. The leaves are alternate with a lobed margin.

The male flowers are in yellowish, slender, pendent catkins about 3 to 8 (10) centimetres long, the tiny globular female flowers are grouped in clusters of two to three on erect stalks one to three centimetres long; they appear at the beginning of May. The fruit, or acorn, is a brown elliptical nut sometimes with darker longitudinal stripes, borne in a cup on a long stalk.