Thoughts on hardwood thinning with chalara fraxinea on the horizon

[Big J]

I'm putting in a proposal for a fairly large thinning operation on an amenity woodland in Devon. It's in a valley with a public right of way at the base of the woodland, next to the river. 

 

The woodland is a mixed species, mixed age stand, with the dominant species being ash and hornbeam. There are a number of oak, sycamore, beech and sweet chestnuts amongst them. In the understory, there is very strong natural regeneration with hazel, hornbeam and sycamore dominating. The mature trees are generally 40-60 years old and the regeneration much younger, ranging from 10-20ft mostly.

 

Having taken another wander through the stand today (and also trying to figure out to get the timber out of the valley) I'm reflecting on the best approach as regards thinning the existing stock. With ash dieback getting a foothold across England, I feel that there is no point in retaining the ash in the long term. The issue is that within this stand 50% of the mature stock is ash in some areas. The hornbeam is the next most dominant species, but as previously mentioned, the regeneration in the lower story is very strong. 

 

My feeling is that in proposing the thinning, my focus should be almost exclusively on ash, retaining them only when removing them would leave nothing else in the area. Conversely, removing trees of other species would only be done if they are densely packed and crowding each other out. 

 

It's an attractive woodland with very good continuous cover. I want to make sure that we take the right approach, and my feeling is that focusing on removing the bulk of the ash would be correct. If I were to perform a more general thin and the ash died within the next decade, it would leave large holes in the cover. 

 

How are other people adapting their thinning policies in the wake of chalara?

[Saw-sick Steve]

I seem to be of a minority viewpoint when it comes to Ash in that from a personal standpoint I'm only removing trees that are obviously beyond saving. I planted a fair few acres of predominantly Ash some 12 years as coppice for firewood, and the majority are now showing varying symptons of dieback. If the worst case scenario comes to pass and we lose 95-98% of our Ash, it'll be a tragedy if the tiny percentage that are naturally resistant to Chalara are removed, as they would hopefully provide a reservoir of resistant seeds to repopulate the countryside.

  Ash, unlike e.g Elm, is a prolific seeder and if enough resistant trees are allowed to stand, re-population could be achieved within a comparatively (ecologically speaking) short space of time.

[slack ma girdle]

I am only removing/ thinning Ash that's crown is is showing >50% die back. Out there are resistant Ash, and I don't want to loose them.

[Big J]

I came across a couple of standing dead ash within the stand, which is something I've rarely seen before. 70ft trees, completely dead. 

 

The floor of the woodland is prolific with regeneration, amongst which would presumably be resistant ash. 

 

Interesting perspectives though. Having done a fair amount of elm clearance up north, my first instinct is to simply clear and start again, but I appreciate that it's not appropriate for all sites.

[timberonabike]

We're currently in the middle of a job with very similar mix of species in a RAWS woodland where we are tackling the thinning of 25-30 year old regen'.

 

Before Chalara, thinning would have very much favoured keeping the ash, especially as the site is well linked historically to ash and they make up the majority of remaining maidens. However, we are now looking at them on a far more equal with the other species. Sweet chestnut isn't that common on the site, so those are left to grow on along with the elm, oak and hornbeam that's also encouraged. Sycamore we don't feel the need to penalise like some do, it will be the species that most likely fills the gap left by ash. Beech is quite a light thief and probably worse for the woodland than the remaining conifers as nothing grows underneath at all, so that is a pretty much default removal. Hazel is all coppiced first so that we can actually see the wood, working on a coup by coup basis.

 

Overall, we're mostly selecting on canopy gaps and haloing our maiden and larger trees and the odd glade from removing big beech clusters and stuff that has been terrorised by squirrels. Not a lot of need to select for market, it's all desirable firewood and all good processor sized stuff, so had buyers lined up before we even thought about starting.