644 PRACTICE OF AGRICULTURE. Part III. 



Sect. IV. Mixture of Trees in Plantations. 



3958. The object of mixing trees in plantations is threefold : that of sheltering the 

 weaker but ultimately more valuable kinds by the stronger and hardier ; that of drawing 

 as much profit from the soil as possible ; and that of producing variety of appearance. 



3959. With respect to shelter, many situations are so exposed, that it is extremely diffi- 

 cult to rear trees without some mode of protecting them from the cold winds of spring 

 during their early growth. This is sometimes done by walls, the extent of whose influ- 

 ence, however, is but very limited ; by thick planting ; or by planting the more hardy 

 and rapid-growing species, to nurse up and protect such as are more tender, but ultimately 

 more valuable. The proportion of nurses to principals is increased according to the 

 bleakness of the site : Pontey says, " Both authors and planters are in the habit of err- 

 ing egregiously, in regard to the proportion of principals and nurses, as they generally 

 use as many or more of the former than the latter, though it is very easy to show, that 

 they ought to use three times as many of the latter as the former. For instance, when 

 trees are planted at four feet apart, each occupies a surface of sixteen feet ; of course, 

 four of them will occupy sixty-four, or a square of eight feet ; and, therefore, if we 

 plant three nurses to one principal tree, all the former might be displaced gradually, and 

 the latter would still stand only eight feet apart." 



39()0. Nurse plants should, in every possible case, be such as are most valued at an early period of 

 growth. The larch and sprUce fir should be used liberally, in every case where they will grow freely ; still 

 it is not intended they should exclude all others, more particularly the birch, which has most of the 

 properties of a good nurse, such as numerous branches and quick growth, on any tolerable soil or 

 situation. It is not, however, like the others, a wood of general application. [Profitable Planter, p. 113.) 

 Sang also adopts the proportion of three nurses to one principal, and employs chiefly the resinous tribe, 

 and looks to them for reimbursement till the hard timber has attained to a foot in diameter, under 

 which size hard timber is seldom of much value. His principals are planted at from six to ten feet 

 apart, according to the soil and situation. {Plant. Kal. p. 166.) 



3961. In procuring shelter, much depends on the mode of commencing and continuing plantations on 

 bleak sites. Sang, who has had extensive experience in this part of planting, observes, that " every 

 plain, and most tiekls and situations for planting in this country, have what may be called a windward 

 side, which is more exposed to the destructive blast than any other. It is of great importance to be 

 apprised of this circumstance, and to be able to fix upon the most exposed side of the proposed forest 

 plantation. Fix, then, upon the windward side of the space which is to be converted into a forest, mark 

 off a horizontal stripe or belt, at least a hundred yards in breadth. Let this portion of ground be 

 planted thick, say at the distance of thirty inches, or at the most three feet, with a mixture of larch, 

 sycamore, and elder, in equal quantities or nearly so, if the soil be adapted for rearing these ; but if 

 it be better adapted for Scots pines, then let it be planted with them at the distances prescribed for 

 the above mixture. We have no other kinds that will thrive better, or rise more quickly in bleak 

 situations, than those just mentioned. When the trees in this belt or zone have risen to the height 

 of two feet, such hard- wood trees as are intended ultimately to fill the ground should be introduced, 

 at the distance of eight or ten feet from each other, as circumstances may admit. At this period 

 or perhaps a year or two afterwards, according to the bleak or exposed situation of the grounds, 

 let another parallel belt or zone, of nearly equal breadth, be added to the one already so far grown 

 up, and so on, till the whole grounds be covered. It is not easy here to determine on the exact 

 breadth of the subsequent belt or zones; this matter must be regulated by the degree of exposure of 

 the grounds, bv the shelter afforded by the zone previously planted, and by such like circumstances." 

 {.Plant. Kal. p 29.) 



3962. In situations exposed to the sea hreexe a similar plan may be successfully followed, and aided 

 in effect by beginning with a wall ; the first zone having reached the height of the wall, plant a second, 

 a third, and fourth, and so on till you cover the whole tract to be wooded. In this way the plantations 

 on the east coast of Mid Lothian, round Gosford House, were reared ; in Sang's manner, the mountains 

 of Blair and Dunkeld were clothed ; and examples, we are informed, might be drawn from the Orkney 

 and Shetland Islands. 



3963. The practice of mixing trees, with a view to drawing as much nourishment from 

 the soil as possible, and giving, as it used to be said, more chances of success, Avas till 

 very lately generally approved of. Marshal advises mixing the ash with the oak ; be- 

 cause the latter draws its nourishment chiefly from the subsoil, and the former from the 

 surface. Nicol is an advocate for indiscriminate mixture {Practical Planter, p. 77.), 

 and Pontey says, " Both reason and experience will fully warrant the conclusion, that 

 the greatest possible quantity of timber is to be obtained by planting mixtures." {Prof. 

 Planter, p. 119.) " We are clearly of opinion," says Sang, ," that the best method is 

 to plant each sort in distinct masses or groups, provided the situation and quality of the 

 soil be properly kept in view. There has hitherto been too much random work carried 

 on with respect to the mixture of different kinds. A longer practice, and more ex- 

 perience, will discover better methods in any science. That of planting is now widely 

 extended, and improvements in all its branches are introduced. We, therefore, having 

 a better knowledge of soils, perhaps, than our forefathers had, can with greater certainty 

 assign to each tree its proper station. We can, perhaps, at sight, decide that here the 

 oak will grow to perfection, there the ash, and here again the beech ; and the same with 

 respect to the others. If, however, there happen to be a piece of land of such a quality, 

 that it may be said to be equally adapted for the oak, the walnut, or the Spanish chestnut, 

 it will be proper to place such in it, in a mixed way, as the principals ; because each 

 sort will extract its own proper nourishment, and will have an enlarged range of pastur- 

 age for its roots, and consequently may make better timber trees. " 



