Low impact forestry services in Devon and the South West

[Brians]

Great pics @Big J delighted to see the Vimek is working out for you. Seems to be a great machine. I recently read a thesis that showed that bigger machines were actually more low impact in thinnings than smaller machines as they have to make less passes to get the timber out. I'd be interested in your thoughts on this if you wouldn't mind...

[Big J]

7 hours ago, Brians said:

Great pics @Big J delighted to see the Vimek is working out for you. Seems to be a great machine. I recently read a thesis that showed that bigger machines were actually more low impact in thinnings than smaller machines as they have to make less passes to get the timber out. I'd be interested in your thoughts on this if you wouldn't mind...

It is a really good machine - the crane is superb, particularly. 

 

I'm back in the Komatsu at the moment on a very, very boggy site in Somerset. The Vimek wouldn't have a hope in here. It's a clearfell too, so no point really. I did have to fully offload myself first thing this morning to get out of a new soft spot, as I'd sunk about 110cm down at the back end (to about 10cm past the band tracks).

 

Anyway, as regards your question about impact on thinnings, I would argue that generally, smaller machines are better. Yes, they make more passes, but they also travel far further away from the stems of the retained trees, reducing root compaction. My experience of working on a few bogs over the past two years is that it's absolute weight, rather than pounds per square inch that is the key factor. The Komatsu fully loaded is 28 tonnes. The Vimek is 9 tonnes. Ok, the Vimek has to make three passes when the Komatsu makes 1, but equate it to road haulage and the 4th power rule. This relates to axle weight, and how a doubling of axle weight is reckoned to cause 16 times the damage to the road surface.

 

From my empirical observations, this is very much the case. We did a boggy site 18 months ago, and I took about 200t across a causeway (built up stone track) over a stream with a pipe going under the track. Over 100 runs with the Logbullet and the track was still fine for driving a van along. One single pass with the harvester (Komatus 931, about 18t) and the causeway was severely damaged and the pipe carrying the small stream crushed. 

 

In addition to the much reduced ground impact, you're also able to take substantially narrower racks with the smaller machines, which improves wind firmness. 

 

In conclusion, machines like the Vimek are slower and less productive, but I much prefer using them and the woodland is much better off in the end.

[Brians]

Good points @Big J I didn't consider the smaller machines travel further away from the roots of the retained trees due to their narrower footprint. Also, as you outlined in your example, the smaller machine has less chance of breaking the surface.

I've attached the thesis for reference, it's old but is a good study. It notes that the damage is normally done in the first 6 passes and subsequent passes don't add much in terms of damage so that would add to your argument for using smaller machines: https://research.thea.ie/bitstream/handle/20.500.12065/1409/Cyril_Furey.pdf?sequence=1&isAllowed=y

Unfortunately, in Ireland, from what I can see there doesn't seem to be much demand for the smaller machines as most forestry owners will go for the lowest price regardless of they type of machine proposed to do the work.

[Big J]

17 hours ago, Brians said:

Good points @Big J I didn't consider the smaller machines travel further away from the roots of the retained trees due to their narrower footprint. Also, as you outlined in your example, the smaller machine has less chance of breaking the surface.

I've attached the thesis for reference, it's old but is a good study. It notes that the damage is normally done in the first 6 passes and subsequent passes don't add much in terms of damage so that would add to your argument for using smaller machines: https://research.thea.ie/bitstream/handle/20.500.12065/1409/Cyril_Furey.pdf?sequence=1&isAllowed=y

Unfortunately, in Ireland, from what I can see there doesn't seem to be much demand for the smaller machines as most forestry owners will go for the lowest price regardless of they type of machine proposed to do the work.

An interesting article. I skimmed over it, but will look more closely this weekend. 

 

It confirms what I was thinking, which is that the majority of damage is done by the forwarder, not the harvester. The Vimek really is an excellent first thinnings forwarder, working in conjunction with a conventional harvester. It's so small in the rack that tree damage is reduced, root compaction is almost eliminated and it's genuinely enjoyable to operate. 

 

I've been back in the Komatsu on full bog this week on a clearfell and haven't enjoyed it much. I've not been properly stuck (though I had to unload myself fully once to get out) but I had to pull the harvester out twice. These photos are actually from the main haul routes. 

 

I'm not concerned about the ground damage, as the whole site is getting majorly remodelled next week with excavators digging a network of drainage ditches and ponds throughout the site. Hoping to improve the biodiversity, but also the productivity. It's mostly eucalyptus nitens going back in.

[Big J]

There is a mountain of brash and chipwood under the track too.

[Big J]

Much more satisfying though was a first thinning we did just before in Cornwall. Ponsse Ergo harvester and me on the Vimek. Shout out to Matt Storrs for the site tidy up at the end. The landowners are delighted, have made a bit of money and it'll keep growing rapidly now (the photo with my hand on a log is one of the larger first lengths of Sitka, at 21 years old).

 

The photo with the harvester is us taking the line of trees back from a powerline.

[Big J]

It's hardly low impact but the guys are having some fun brash raking and digging ditches on our current site. The mud you see on the back of the machine is how far down he went. Where he's presently sat is just standard for working there. 

 

It was interesting watching him work - it was like the machine was sat on a massive trifle, such was the solidity of the ground. 

 

And we also dug the neighbouring woodland owner a pond as a thank you for putting up with the disruption. He was absolutely delighted. 90 minutes well spent.

 

Edited April 26, 2021 by Big J

[topchippyles]

10 minutes ago, Big J said:

It's hardly low impact but the guys are having some fun brash raking and digging ditches on our current site. The mud you see on the back of the machine is how far down he went. Where he's presently sat is just standard for working there. 

 

It was interesting watching him work - it was like the machine was sat on a massive trifle, such was the solidity of the ground. 

 

And we also dug the neighbouring woodland owner a pond as a thank you for putting up with the disruption. He was absolutely delighted. 90 minutes well spent.

 

Big J what is the price of larch road side at the moment please mate. Local woodland near me has some available but i have to collect and mill on site due to disease infection.

[trigger_andy]

Big J what is the price of larch road side at the moment please mate. Local woodland near me has some available but i have to collect and mill on site due to disease infection.

What they asking for that?

[Khriss]

23 minutes ago, Big J said:

It's hardly low impact but the guys are having some fun brash raking and digging ditches on our current site. The mud you see on the back of the machine is how far down he went. Where he's presently sat is just standard for working there. 

 

It was interesting watching him work - it was like the machine was sat on a massive trifle, such was the solidity of the ground. 

 

And we also dug the neighbouring woodland owner a pond as a thank you for putting up with the disruption. He was absolutely delighted. 90 minutes well spent.

 

Ponds are the  way forward, we have lost hundreds  of them in England. K