Chestnut trees: snapping, splitting and propping

Chestnut trees are very brittle, and large branches (sometimes 400 mm in diameter) often snap in storms. I have realised that matters are made worse if branches are forced to grow upwards by being planted too close together, since the branches of trees that have plenty of space grow downwards until they reach the ground, which supports them. Hence the tree that has suffered the most fractures is the centre one of three, with the third, which is flanked on the other side by a walnut, a close second. I was starting to instal the props last autumn, but was to late for one branch of the fourth big chestnut, which is quite separate from the others. A big low branch that came close to the ground split under the weight of the crop . I had a man come to quote in lifting it with machinery so I could prop it, but by the time he arrived the top arm of the split had fractured, which the you could see the stress fracture in the lower (Figs. 1, 2). So lifting was not an option, s what I did was what I should have done in the first place, which is to prop it as it was. With spring it burst into leaf, which is hard to believe given how little of the trunk is left. Either this will peter out in the summer and die off, or else it may struggle on, perhaps with half the branches dying off In the latter case, the branch will remain as a mighty ruin.

Fig_01_Split_Chestnut_A_0732_1000

Fig_02_Split_Chestnut_B_0733_1000

This really motivated me to attend to the other trees, especially the big Number One tree, which is the one that spreads the most (Fig. 3).

Fig_03_Trunk_1013_1000

Unfortunately, on the north side the branches cross the neighbour’s boundary. The branches on this side were lopped years ago, but have grown vertical trunks. I managed to head off the neighbour’s efforts to cut back hard to the fence line, and to get them to let me prune it more sensitively so that it is well free of their house. Fortunately they were away for a couple of weeks, so I pruned it again the other day. Seen from there side of the fence they get a wonderful leafy cave (with daffodils and bluebells beneath in late winter and early spring); the view from my side is not so good. I propped these branches. Much too big is a whopper trunk that grows upwards over the Woodshed Temple. It must be 600 mm in diameter lower down, and then goes up almost vertically at the fence line. Because it does not extend laterally very far I hope that it is secure. To prop it I would need to put a 5 metre pole up in the narrow space between Temple and fence line.

This left the south side of Number One, which has the longest branches, which extend as squiggly snakes for tens of metres (Fig. 6). There have been some fractures, but several of the branches reach the ground. Some have split, but because they were so close to the ground, the splits are not too bad. I levered these off the ground and put low props under them, partly to be able to clear around them properly (these areas have been impenetrable for years), and partly for fear that the branches resting on the ground would rot. Yet one branch could not be lifted, and seemed to have taken root (Fig. 4).=

Fig_04_Rooted_Branch_1010

 

 

 

I was not sure if this was what really happened, until I lopped one small branch off another big one, and when I pulled it out of the ground it had roots growing out of it (Fig. 5).

Fig_05_Root_Hairs

So it seems that chestnuts layer like rhododendrons, and theoretically could propagate themselves over a considerable distance in this way. It is very Fanghorn forest.  So my levering off the ground was actually unnecessary, and possibly harmful. The higher props, however are very necessary. The biggest worry are high branches that are 300 mm or so in diameter and extend laterally 20 m or more. One of these actually rests on another below it (Fig. 6).

Fig_06_High_Branch_1014_1000

This seems to be a breakage waiting to happen, and I am debating whether this warrants an 5 metre pole as a support. It would be both difficult to attach at the top (my ladders don’t go this high) and unsightly.

I gradually evolved a way of installing the props (Fig. 7).

Fig_07_Chestnut_Props_crop_1012_1000

These big trunks are surprisingly rigid, even 10 metres out, so are hard to lift. I look for a flat point in the right place and drop a vertical, where I place a sole plate of treated pine about 400 to 500 m long by 200 wide and 50 thick, which is dug a little into the ground. Then I measure the pole distance, plus a bit. I prop the pole at an angle and then put a strap of plastic garden edging over the branch which is screwed to the pole on both sides with hex head tek screws. (These are the only screws to use if you want to be able to disassemble things at a later date.) Then with the back of a wood splitter (i.e. a mallet) I bash the lower part of the pole and the sole plate toward the vertical, using a spirit level to get it right. This is enough to put pressure on the pole and plate to keep it all in place. Then I screw the pole to the plate, and cover the plate a bit. This is now quite firm. The trick, of course, is to do the job in winter (actually late spring now) before the chestnuts add extra weight, but at the moment the bulbs have died back and access is easier.

I measured the circumferences of the tree approximately with the metal tape (Fig. 3). It is is about 4.4 metres.

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