Hello all, What everyone thus far has said is relevant. Jon's rule-of-thumb of 0.9 x distance from row centre to row centre is good, but not a complete answer. To get to the bottom of this very difficult question requires information like light intensity (the more intensity the better the canopy penetration), latitude (determines average angle of incident light, and consequently shading effects) and proposed width of actual tree row from edge to edge, to name just three factors. Also, it should be borne in mind that in reality most growers do not wish to achieve maximum yield, but rather a balance between maximum quality and yield, and after a certain point, I have no doubt that raising yield further results in lower quality (in terms of soluble solids/sugars in the fruit, in terms of fruit size, and to an extent, fruit colour). Unfortunately I do not have a formula to offer. However, I have been in orchards in different parts of the World, and can say with certainty that one size does not fit all. In my own experience, I have never seen light intensity that matched that in the apple growing area around Hawkes Bay in New Zealand. There I saw orchards with what I would have considered trees which would not allow for enough light penetration. But the light intensity was such that it did penetrate, and what would usually be unproductive inner parts of the tree had apples and leaves, and indeed I was told by my host that the particular orchard of Granny Smith had yielded 150 tons per ha in the past, and I could well believe it. When I visited northern Italy, I saw the most perfect trees trained to a fruit wall, and they must have been perfect 0.9's; just like Jon is suggesting. It was self-evident that light would get to all parts of the canopy, that there would be no unproductive inner canopy due to the narrowness of the tree hedge, and that the balance of yield and quality would be excellent. Having looked at a similar tree wall of about 3.5 metres tall in Belgium close to harvest time, I was disappointed to note that the apples growing on the lowest 50 cm of the wall were poorly coloured and only of juicing quality. In time, this part of the canopy would be lost due to less than optimum light penetration, and that told be that the tree rows were 50cm taller than ideal, as the top 50cm was shading the bottom 50cm. Put simply, in my opinion, for that orchard in Belgium, the 2.5 metres of productive wall should start at 50 cm above the ground, and finish at 3 metres tall; not at 3.5m. In my own orchard in Ireland at more than 52 degrees N, I can only manage a productive canopy of about 2 to 2.2 metres tall (when rows are 3.25 to 3.5 metres apart). If I go taller, then shading of bases becomes a problem again. One of my favourite pastimes is to go into the orchard on a sunny day (we get more cloudy days than sunny ones), and look at where the shadows fall. I know I am correct in my assessment of maximum height for the quality I want to grow, given the light intensity I have to work with. So Art, it is ultimately up to you; you should have an idea of your own situation, and the quality of fruit you want to grow. Experience may in time tell you that you pushed a bit too far, or that you did not go tall enough. I would not recommend deciding your tree height and then your row centres. I would prefer to decide on row centres and thickness of the canopy (to suit machinery, operations etc.) and then work out how high the trees should be allowed to grow. Have fun.
Con Traas The Apple Farm Cahir Ireland _______________________________________________ apple-crop mailing list [email protected] http://virtualorchard.net/mailman/listinfo/apple-crop
