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THE ART OF PLANTING FARM TREES

Most farmers intending to plant trees will run a deep rip—that is, deep enough to fracture the clay below the top soil—along the line where they want the trees to be planted. Farmers normally plant trees in the rip line—that is, along the line where the ground is broken—the idea being that the trees will find their feet quicker if their roots can spread through the broken soil. Moreover, water tends to get trapped in the rip lines, and having been trapped there it can easily penetrate to the bottom of the rip where the trees’ roots are.

Experience has taught me to do things a little differently, however. As a general rule I do not plant right in the rip lines but, rather, slightly to the side. Why? Because I have found that rip lines in our heavier clay soils are liable to get either too wet from pooling water during winter or too dry during a dry spell, the reason being that water evaporates from them freely. I have also found that if you plant a tree just off the rip line its roots will bond better. Again, this is not a hard and fast rule. When it comes to planting trees, you cannot have hard and fast rules, for how exactly you plant a tree depends both on the site and on the species and size of the seedling.

For planting large numbers of trees in the form of tube stock I use a tool called a Hamilton Tree Planter, an implement I had a hand in developing. When I first started planting trees at Lanark I fashioned a crude tool that enabled me to open holes in the ground just big enough to receive the tube stock I was planting. It consisted simply of a length of rounded hardwood with a bolt through it, on which I could press with my foot to force the tool into the soil. Keith Cumming, then a local officer of the Pasture Research Institute, got to know of my planting tool, and he used it later as the basis for a more advanced piece of equipment of his own design, which came to be known as the Hamilton Tree Planter.

The Hamilton Tree Planter roughly resembles a garden fork, except that instead of the prongs there is a steel container the size and shape of an ordinary plant (forestry) tube. When you pull it out you remove a divot of soil the same size and shape as the tube. You simply drop the tree in the hole and tramp down the surrounding soil. As you drive the planter into the ground when planting the next tree, the soil already in the container will be forced out. I used this surplus soil to cover the top of the soil around the young plant. This surplus acts as a mulch, helping prevent the plant drying out by reducing evaporation from the potting mix in which the plant is growing.

We have used nurse trees in many of our forestry plantings. Nurse trees are planted to protect and shape the timber trees that you intend to grow. For instance, if you wanted to plant a group of she-oaks, you might alternate them with black wattles as nurse trees. The black wattles grow faster than the she-oaks, so they shelter them. If the black wattles are planted close enough, they will also force the she-oaks to grow up straight. The usual practice is to get rid of the nurse trees once they have done their job, although I do not do this myself. I usually leave the nurse trees, which, in any case, will probably die before long of their own accord, since they are invariably short-lived species.

Here is one example of a successful nurse-tree planting at Lanark as I recorded it in my tree journal. In the spring of 1984 we planted river she-oaks, a fine timber tree, along with black wattles as a nurse crop in what we named the Pulleyblank Plantation. In March 1994, I wrote in the journal that I had removed the biggest of the black wattles. So for almost ten years the she-oaks had been protected by the wattles and, as I noted in the journal, they were doing well. Obviously enthused by the success of the whole planting, I went on: ‘We also have shelter, shade, landscape (aesthetics), firewood, untreated temporary fence material for on-farm pine agroforestry plantings, tops on ground for mammals, spiders etc., spars for the new chook house, shed for Murray Gunn’s seed bank. All this from the black wattle nurse crop. The river oaks grow on—maybe for another 50 years.’

What you should never do when planting trees is put them out along the line at the required intervals before planting. Many people do this without realising that the trees’ hair roots can get burnt off while the trees are lying there, waiting to be planted. Before planting, I would first stand the trees for a short while in a bucket of water and then carry them about in a damp jute bag.

On the question of watering: the fact is I did not water most of the tree species that I planted. I certainly did not water natives and conifers. I found that provided you supersaturated the tube stock before planting, by standing the tubes in water—and provided you had the correct planting technique—there was no need to water the trees once they were in the ground. One other proviso needs to be added here: you must ensure that the trees you are planting do not have to compete with weeds. This means that you must spray out the tree line before planting to kill any weeds, and you must maintain weed control for at least two years.

Of course, long before you start planting trees you have to decide where to plant them. A mistake farmers often make is to plant trees alongside an existing fence. In other words, they allow the location of a fence that may have been erected half a century ago to determine the location of the trees they intend to plant tomorrow. Now, this is fine if, by a nice coincidence, it happens that the best place to plant the trees is alongside an existing fence. After all, using an existing fence as a boundary for a row of trees does mean you will have one less fence to erect. But it is crazy to plant trees along an existing fence if this is not the best place to plant them.

I have been guilty of this myself. Jim Sinatra used to bring groups of his students to Lanark on field days. Before one such visit, I had pegged out the site of a row of trees I intended planting. I had it running down a hill alongside an existing fence. Jim Sinatra’s students saw the folly of it immediately. Why plant the row of trees there, they asked, when it cannot possibly protect the sheep from wind, given that the prevailing winds blew from another direction?

Visitors to Lanark often comment on the fact that many of our smaller plantations of trees—areas of up to an acre or two (0.4 to 0.8 hectares)—have been fenced off in circular lots. Some are decagons with ten sides; others have 25 sides (icosapentagons). Why not simple squares and rectangles? It all has to do with the way sheep move around corners. If you plant your trees in a square or rectangle—that is, with right-angled corners—you will find that the sheep tend to wear out deep tracks around each corner which in time will lead to erosion. This is simply because the sheep repeatedly cut around each of the four corners while moving from one part of the paddock to another. But if you plant your trees in an icosapentagon, which is virtually a circle, the sheep tend to disperse, so the tracks they wear are not nearly so deep and damaging. Anyone wanting to know more about these circular configurations would do well to consult Rod Bird’s 2000 book, Farm Forestry in Southern Australia.

There is another important consideration: appearance. Circular shapes look more natural and so fit into the landscape better. They certainly suit big, spreading trees like river red gums, for the fences forming the circles more or less approximate the trees’ drip lines. Whereas many farmers plant red gums as stand-alone trees out in the paddock, we have always preferred to plant a number of them towards the middle of a decagon and surround them with wattles and various other habitat plants. Wattles fix nitrogen and are therefore good companion trees. Our hope is that 50 or even 100 years from now, when the fences forming the decagons finally fall down, a few red gums will be left standing.

I cannot stress this enough: the key to growing trees successfully is to eliminate competition. You must maintain good weed and grass control around the trees you have planted. Someone asked me recently if I used water crystals when planting trees. I replied that I considered water crystals a waste of money. Provided you maintain good weed control, water crystals are not necessary. Weeds are the number-one cause of young trees being deprived of water. I may add here that I do not mulch trees when I plant them, either. I used to do it. In our early years at Lanark, Cicely and I spent weeks mulching plants, but I realised eventually that it was not necessary. Again, provided your trees are of a species that suit the conditions and provided they do not have to compete for water with weeds and grass, they do not need to be mulched.

At Lanark, we made a practice of giving every planting a name. Usually, we named each planting after someone who had something to do with it. Even individual trees were given names. For instance, there is an oak on the place that we call Clive’s Oak, the reason being that our oldest grandchild, Clive, planted it when he was a toddler. Naming plantings like this serves a practical purpose: it makes the plantings easy to identify and therefore easier to manage. It also personalises the plantings and reminds us of the friends and relatives who have helped us with projects.