Monday, March 8, 2010

Pruning season is here!!

Mark your calenders for saturday april 3rd at 9am. Strafford county cooperative extension is hosting a fruit tree and bush pruning demonstration here at Butternut Farm. Two of our great county extension agents will be here including Geoffrey Njue and Bill Lord to help clear up the "how to" on pruning fruit trees. Also early spring is a great time here at Butternut Farm because everything is very green and the weeds have not emerged yet. So come out and enjoy a great morning walk around the farm with us.
Well March is the month to start getting those apple trees pruned. I started pruning ours here at Butternut in February to stay on schedule because it takes me some time to get thru them all, but if you have just a couple of trees then any time in march or early april is the best time to prune your apple trees.
If you are not as familiar with pruning fruit trees as I am it may seem a little like reading greek. Well maybe if I describe the thought process I go thru when I prune trees it may help you make some decisions when looking at your trees with the loppers in your hands.
First things first, young trees. Lets call young trees anything 5 years old and younger. These trees are actually very simple to prune. Any young tree out there is most likely planted on a dwarfing rootstock so the central leader pruning system is the tree design of choice. My goal is a tree shaped to look like a christmas tree with lateral fruiting limbs progressively getting smaller as you move up the tree. The simple way of doing this is to entirely remove any limb that is overly vigorous, upright and competing with the central leader of the tree. The way I decide this is if the branch diameter is half the size of the tree trunk where they connect then it needs to be removed. These strong lateral branches will compete for dominance with the central leader of the tree resulting in a less fruitful tree which is more difficult to manage down the road.
Once a tree is full grown which for me is a tree about 12 feet high the thought process changes a bit. The same christmas tree shape is still desired so strong upright limbs are always removed especially in the top half of the tree. Now though you must start thinking about light penetration into the whole tree. The tree is now big enough that if left on its own it will shade itself out and productivity will be lost in the middle and lower part of the tree, so it is up to the pruner to counter this natural tendency of the the tree. "Thinning" cuts are now used, they are very similar to whole limb removal cuts of overly aggressive lateral limbs on "young" trees only now on a full grown tree you may have to cut out some good branches to allow proper light penetration to the ones left intact. This is where it gets more difficult to make decisions. I make my decisions based on these concepts: the bottom tier of branches should consist of 3-4 evenly spaced lateral limbs. These bottom branches are allowed to get larger in diameter but are kept in check with "heading cuts". These are cuts made on the ends of lateral branches to keep them from getting to long. Over the years these heading cuts should produce a nice "spreading" bottom tier of 3-4 scaffold branches. Now above this bottom tier I try to continue whole limb removal as my primary cut I make. As mentioned heading cuts induce lateral spreading of branches which stiffen branches and allow them to get bigger producing more shade for the bottom of the tree. I try to keep my branches above the bottom tier weak and small in diameter, at most one third the size of the trunk where the branch and trunk connect.
Now if you are a homeowner with just a couple of trees in the back yard most likely they were never pruned to the central leader system. They may now be big and umbrella shaped or maybe have not been pruned in a couple of years and just look Bad. So here is where the "art" of pruning comes in. And that is what pruning is. There are never any right or wrong decisions when pruning apple trees. The only "wrong" pruning cut is the one not made because people always tend to leave to many limbs on a tree and we know what that leads to. So I always attack larger trees first with a chain saw. Yes a couple of larger "thinning" cuts made with a chain saw back into the heart of the tree can do a world of good for older trees. Again I target larger wood with an upright growth habit to remove. Upright wood produces vigor and lateral wood produces fruit, remember this when making cuts. Also remember pruning is a renewal process. That means old wood is removed and young wood is left to fill the voids left when a larger limb is cut out. If you get into a habit of "nipping" a tree and cutting off just small limbs eventually all you will have left is a tree with a whole bunch of fire wood sized branches. Large fruiting limbs equal old buds, small fruit, and a lot of vigor. Small weak fruiting limbs equal young fruit buds limited shading of the rest of the tree and larger apples.
A lot to think about but just remember pruning is an art. There are no right or wrong cuts. The saying goes put 5 farmers together to prune one tree and they all will do it differently. They all can't be wrong! The only wrong thing to do is nothing! So go get your pruners sharpened, gas up the chain saw, and go make some cuts this weekend.

Thanks for reading!