Hybrid poplar plantation growth rates?

[Big J]

We're working a primarily larch site at the moment which has a strip of stunted spruce at the foot of the hill. The spruce is being 80-90% removed as the hybrid poplar species (I think, possibly aspen, need confirmation) that is planted amongst the spruce absolutely towers over it.

 

The whole plantation is 30 years old. The larch has done quite well, averaging 0.4 cube or a touch over, at 60ft height. The spruce has been suppressed so is only about half that size, but the poplar (same planting year) averages about 3-4 cube, 100ft + tall and some trees are nudging 6-7 cube. It has also grown with perfect form and would fly through a (very large) harvester head. 

 

They had to clearfell the neighbouring block due to the poplar towering over the spruce, and them being unable to get the poplar out without smashing the softwood. The funny thing is that all of the poplar stumps have regenerated and even the brash from the poplar has rooted and is growing with great gusto. That operation was done 2 years ago, and the douglas fir that has been replanted is only 2ft tall and the poplar is over 12ft or more, and that's with efforts by the forestry management company to kill it.

 

This epic growth rate and relentless determination to not be killed off has got my brain cogs going and I'd love to establish a little plantation block with the stuff. I'll get some photos of the trees next week for species confirmation, but has anyone planted a poplar plantation for biomass and what sort of growth rate did they achieve? This particular strain seems to be way off the charts as regards normal yield class. A 60cm DBH tree at 100ft just isn't normal for 30 years old.

[The avantgardener]

With those growth rate figures I would be surprised if it was Aspen. I think it would be more likely to be one of the Black Poplar hybrids, I have seen them develop at extraordinary rates both here and in France in the right growing conditions.

Post some pics of the bark/leaf on your next visit.

To plant, final thin and clear fell a site within your own lifetime would be quite something.

[Big J]

4 minutes ago, The avantgardener said:

With those growth rate figures I would be surprised if it was Aspen. I think it would be more likely to be one of the Black Poplar hybrids, I have seen them develop at extraordinary rates both here and in France in the right growing conditions.

Post some pics of the bark/leaf on your next visit.

To plant, final thin and clear fell a site within your own lifetime would be quite something.

 

I did wonder if it was a bit too quickly grown to be aspen. But then neither myself or the forestry manager (more experienced than me) could quite put our finger on what it was. I'll get photos.

 

I did some quick calculations/projections on the basis of the final crop at 25 years being half the volume of what I'm seeing in this stand (trying to err on the side of caution) and it worked out that starting with your first thin at 7 years, thinning every 3 years and clearfelling at 25 years, you should be able to profit (after harvesting costs) £1700/hectare per year (not including planting costs). Given that farmland is around £15k/hectare around here, it's quite a good rate of returns, especially considering there is no replanting cost as it coppices so readily. That said, I'd need to confirm the precise growth rates as the trees I've seen on site are so far beyond the size of any normal forestry tree species, they don't fit in any yield class chart I've seen.

[The avantgardener]

All Poplar Species are a doddle to clone and propagate, that would be my starting point if I had a stock with an extremely good provenance.

Edited June 16, 2019 by The avantgardener

[slack ma girdle]

I thined a block of hybrid Poplar (planted 1996) about ten years ago, and is comming up for a second and final thin next year. It is currently about 28m tall with an average dbh around 45cm. So it doesn't surprise me that you have such monster trees.

 

 

[Big J]

21 minutes ago, slack ma girdle said:

I thined a block of hybrid Poplar (planted 1996) about ten years ago, and is comming up for a second and final thin next year. It is currently about 28m tall with an average dbh around 45cm. So it doesn't surprise me that you have such monster trees.

 

 

That's just lunacy Murray. Why on earth isn't it being planted en-mass to supply the biomass market? My best calculations put it at about YC70 (yield class, so 70 cubic metres per hectare, per year), which is double the best softwood output. The vast majority of the trees I've seen in this compartment are harvester processable too. 

 

I just need to find a landowner willing to chuck a couple of acres of low-grade farmland at me so I can experiment!

[Rough Hewn]

Willow is marketed (in France) at 180m3 per hectare every 3 years. Specialist combine harvester mows it and chips it.

[Big J]

1 minute ago, Rough Hewn said:

Willow is marketed (in France) at 180m3 per hectare every 3 years. Specialist combine harvester mows it and chips it.

These are my rough calculations for this particular strain of poplar (I reserve the right to admit that my figures are completely out if indeed they are completely out!) :

 

Planted at 2000/hectare (4 hectares)

10% loss on planting (1800/h)

First thin at 7 years. Trees 0.25 cubic metres, racks at 1 in 7 put in. 257 cubic metres, around £3k profit. (1543 trees/h)

2nd thin at 10 years. Trees at 0.5 cubic metres, step rack 3/4. 515 cubic metres, around £10k profit. (1286 trees/h)

3rd thin at 13 years. Trees at 0.75 cubic metres. Selective, 1 in 4. 964 cubic metres, around £22k profit (964 trees/h)

4th thin at 16 years. Trees at 1 cubic metre. Selective, 1 in 3. 1273 cubic metres, around £32k profit (636 trees/h)

5th thin at 19 years. Trees at 1.25 cubic metres. Selective, 1 in 3. 1050 cubic metres, around £26k profit (420 trees/h)

6th thin at 22 years. Trees at 1.5 cubic metres. Selective, 1 in 3. 694 cubic metres, around £17k profit (277 trees/h)

Clearfell at 25 years. Trees at 2 cubic metres. 2216 cubic metres. £55k profit.

 

That's with a harvesting cost of about £30/t on the first thinning, reducing to £25 ish on second and then £20/t thereafter. The figures are fairly conservative as the 30-year-old poplar on this site are nearer 4 cube than 2.

 

Profitable enterprise and if I was a landowner with 20 hectares of spare grazing, planting poplar would be something I'd seriously look into

[Paul in the woods]

These people are around your area, might be worth popping in for a chat if you're ever passing.

 

https://www.bowhayestrees.co.uk/willow-poplar-varieties

[Big J]

8 minutes ago, EdwardC said:

I planted a few experimental plots with hybrid poplar clones in the mid 70's. I also helped manage other plots in the late 70's onwards. What is clear is that  some clones to better on some sites than others. That shouldn't be a surprise really.

 

When you get your site you will need to think about which clones are best suited. There's plenty of information out there, particularly on the Forest Research site, e.g.

https://www.forestresearch.gov.uk/research/archive-poplars-for-wood-production-and-amenity/

 

There's a reason it's not being planted en masse. It doesn't stack up financially. Of course things may change, but pest and disease is a big problem

That's very helpful. Thanks for the link. I'll study it with more detail later this evening.

 

The site is clay based, but surprisingly dry. I'd have to compare the soil maps for there and around home for comparison. Poplar just seems to do really well around here - I've seen some true monsters.