Winding down for spring

With the rapidly lengthening days, the passing of the equinox and the woods filling with birdsong, it was time to wind down the winter’s woodland work. We stopped felling at the end of March and finished extracting the logs by early May, leaving the birds to nest in peace. I’ve been able to spend one or two days a week working in the woodland over the winter months, with a few local helpers (paid and volunteer) coming to give a very much appreciated hand.

After felling the small (0.1 ha) coupe of poorly grown spruce before Christmas (see here), we moved on to thinning some adjacent areas of better quality spruce trees, covering just under a hectare. I finally purchased a winch for the woodland, which arrived in the new year and was soon put to use extracting the felled logs. This winch has a remote control, which greatly speeds up the process, and it has worked pretty well so far.

Undertaking the thinning work has been a learning process for me. Prior to going in with the saw I had gone in with the spray paint and marked up a selection of trees to fell. Initially I had been very idealistic in my selection, trying to leave every half-decent tree and remove their competing neighbours and other poor quality trees. However, I soon realised that felling these trees, randomly distributed throughout the stand, was going to be very difficult and time consuming. The spruce trees are 15-20 m tall and have never previously been thinned, so are very closely spaced. The upper branches of adjacent trees are often overlapping and the trees seem to stick together like velcro, such that when you attempt to fell a tree it hardly moves, held up by its neighbours, and takes a lot of wrestling to get down. The winch could be used to pull trees down, but doing this for every individual tree would be very slow.

I soon learned to take a more pragmatic approach and selected rows of trees to fell, trying to leave rows with the best trees and remove rows with less good trees. This approach allows the trees to be felled into the gap left by the adjacent felled tree. Trees still sometimes get stuck, but less often. It also means the felled logs are lined up in a series of ‘racks’ and more efficient to extract than logs dotted here and there.

We winched the logs up or down to the track, where they were cross-cut into 3 m lengths and stacked by hand. Because the tractor had to sit on the track, the winch rope had to be re-directed 90 degrees or so into the stand by using a snatch block (pulley) on a tree opposite the rack being extracted. Winching is then simply a case of taking the rope down, hooking on the logs and using the remote control to activate the winch to pull them up or down. It is important to pay attention to the logs as they are being pulled, trying to avoid obstacles like stumps or large rocks. If the logs get stuck behind a stump and the winch keeps pulling then it is quite possible to pull the tractor backwards or pull over the tree that is being used for the snatch block, so the winch operator needs to stay alert!

Being able to work the winch remotely from the tractor is obviously very handy, but it does have the down-side that it’s not always possible to see what is going on at the tractor. On one occasion I had paid out too much rope, which somehow managed to get into a knot. Not realising this, I pulled in, wondering why the logs weren’t moving and unfortunately creating a kink in the wire rope. However, apart from this it has worked very well.

The thinned areas feel more open now, though not overly so, and sunlight can filter through to the woodland floor. The broadleaved trees within the thinned spruce stands also now have more space and light. I have been cautious and tried not to over-thin the stands, mainly because this would expose the remaining trees to a greater risk of wind-throw. (Previously un-thinned stands of semi-mature trees can be susceptible to wind-throw when thinned as the trees have grown up very close together and can be providing mutual stability. Thinning can remove this stability and alter patterns of wind within the stand, making trees more vulnerable.) Another reason not to remove too many trees is that the trees are not yet fully mature and therefore have potential to increase in size and value. One aim of the thinning is to open up the canopies of the better, remaining trees to allow their trunks to grow fatter and taller and eventually produce more timber.

The extraction method using the winch was chosen because of the relatively small impact on the ground and soil, compared with taking in a forwarder to pick up the logs. Forestry forwarders, being big, heavy machines, can cause soil compaction and disturbance. They also tend to operate on larger scales, meaning the selective thinning we are doing here wouldn’t be able to be extracted by such a machine. Small and mini forwarders for thinnings and low-impact forestry do exist (e.g. the Alstor), but our site has many steep slopes where using such a machine would be awkward, so winching seems to be the best solution.

The winching process has caused some superficial ground disturbance where the logs have been dragged over the soil. This is essentially a light scarification. It is no worse than what might be done by a wild boar and should be beneficial in creating a seed bed for regeneration of trees and other plants. It will be interesting to see how the regeneration on the scarified areas of soil (i.e. in the extraction racks) compares with areas of undisturbed soil. This will probably be most important in the felled coupe, which is now clear of trees and therefore has plenty of light to allow regeneration. There is not enough light in the thinned areas to allow tree regeneration, but I’m hoping there will be an an increase in ground flora beneath the stand. Ground flora within the felled coupe are already responding to the increased light levels, with previously suppressed plants like bluebells, wood sorrel, anemone and primrose now growing more strongly, with some starting to produce flowers. These will hopefully now spread across the coupe, with more plants seeding in over time. I’m planning to re-plant the coupe next winter to supplement the natural tree regeneration that I expect to appear.

Now the warmer weather is here it is good to relax and enjoy the woods as they emerge into their spring colours. The birdsong has reached its annual climax, with summer visitors (willow warbler, chiffchaff, blackcap) joining the blackbirds, song thrushes, robins, chaffinches and others. There are a few jobs to do over the summer – a bit of spruce seedling removal, firewood processing, machinery maintenance and planning the next felling work. This winter’s progress has made me enthusiastic for continuing with the work next winter and I’m looking forward to turning my ambitions into plans over the next few months.