Thread: Question: Pollarding effects on Euc.

g'day clinton, I've just got your message. I am working away from home during the week pruning a massive pine block. no communications available.

Your question seems to be related to... can I grow more timber by pollarding and/or copicing. Incidently these terms are essentially the same thing, however traditional pollarding usually takes place higher up the original trunk than coppicing. Historically, pollarding was done to avoid the butt sweep and fluting at the base common on older trees as well keeping the succulent new growth above sheep/cow height.

Back to the question. The answer is essentially No you can't produce more growth by pollarding/coppicing. The key aspect here is Biomass. Any given parcell of land will only produce a given amount of biomass. Whether it is leaf, stem, heartwood, sap wood, roots etc is immaterial.

A given parcell of Land has a given productive capacity.
(called the Site index) Productive capability is governed by underlying soil fertility, rainfall and rainfall spread (the ratio of seasonal rainfall). Underlying productive capacity can be temporarily altered by the application of fertiliser, trace elements, and or irrigation, However once this alteration ceases, land reverts slowly to its underlying productive capacity.

Diameter and height growth can be affected by planting density (up to a point) closer spacing = more height growth. Wider spacing = larger diameter growth. This can be measured by measuring the basal area (cross section of tree at breast height. But essentially the amount of biomass will remain (roughly) the same. A short fat tree will have the same amount of biomass as a tall skinny tree.

here is a really good guide to farm forestry
http://www.mtg.unimelb.edu.au/public...ers_forest.htm
download and save each chapter in case it disapears from the web.

I will pm you with some Qld private forestry extension officer contact emails.

Re the euc Nitens
average ......?circumference?......... of 1999/2000 = 415 mm which is equivelent to 132 mm....... 13 cm. in diameter

Dont forget diameter at breast height in NZ is 1.4m,
in Aust DBH is set at 1.3 m.
Apparently this is because kiwi ladies are perkier than Aussie sheilas.

1989 planting average diameter = 328 mm = roughly 33 cm.

Murray you should contact one of the NZ farm forestry organisations and get some advice on these. They could be worth around $100/150 per stem if form is good and properly managed for timber.

One thing you could do is measure a sample this year (statisticly 2% of trees spread across 2% of land area)
We should use diameter at breast height (1.4m for you).

To work this out either purchase a diameter tape or measure cicumference and divide by pi (3.142) This will give you an average diameter divide this by the number of years since planting.

using the figures you provided avg dbh = 328mm/17yrs=19.29 mm diameter this is your "mean annual increment" (MAI).

Recored these figures then at the same time time the following year measure again.

Subtract the new figures from last years, you will now have established how much growth your trees have made in the last 12 months. This is your "current annual increment" (CAI)

Once current CAI drops below MAI you can see that diameter growth has slowed and it is time to thin some stems to allow the others to grow on.

Of course there is much more to growing and measuring timber than the above so find a local farm forestry scheme and be involved.

http://www.nzffa.org.nz/tree_grower.cfm?tid=24

North Island demand
In the North Island the demand profile appears to be in the sructural and pruned segments with some supplies suggesting they are struggling to keep up with demand. One report suggest some mills in the Wairarapa have had to work short time as logs have run out.
Roundwood post and pole material is in short supply in some regions as foresters move toward the more modern regimes. These regimes are producing faster growing trees with larger branches, and as a consequence, less round wood. Both structural log (S grade) and pruned log prices remain stubbornly stable despite starting to outstrip supply.
(NB applies to pine only)

Originally Posted by Clinton1

The sucker uses the old trees existing root system to feed itself and regrows much faster than any other planting system.
Be good to see what happens to the trees when pollarded.

Clinton

My observations on our property of trees that have coppiced (following me cutting them down) is that they do grow faster then surrounding uncut trees. It seems likely as you have suggested, they benefit from an established root system, particularly in times of stress.

However, because the timber grows faster, it is also weaker. For example as a comparison, plantation timber normally exhibits less strength than non plantation timber of the same species.

I was also told by an old sawmiller friend that they did not touch coppice regrowth. This is a little aside from your original post on pollarding and it's effects, but I would guess the principle is similar.

Regards
Paul

When the CAI drops to the point that it is the lower than the MAI (see
Figure 17), then MAI must fall also, since the increase in the next year will
be less than the average. MAI is a much used (and often abused) forestry
measurement for tree growth, but whenever a MAI or CAI figure is quoted,
the age of the forest must also be known. Because MAI changes with time, a plantation that has grown at 20 m3/ha/yr over 10 years might have 200m3/ha, but if grown for another 10 years it will not necessarily have 400m3/ha.
The effect of stand age on the Current Annual Increment (CAI) and the Mean Annual Increment (MAI) of a Eucalyptus globulus plantation on a very high quality site in Tasmania (Data from Goodwin and Candy 1986).

I should note here that the end product, timber, pulp, firewood or other will affect how the growth characteristics of trees can be used to aid us to economically produce a crop.

http://en.wikipedia.org/wiki/Pollarding

http://www.mntca.org/Newsletter/news...pollarding.htm

http://www.rhs.org.uk/advice/profile...pollarding.asp

http://www.gardengatemagazine.com/ex...pollarding.php

http://www.bluestem.ca/willows-pruning.htm

http://www.afmanconsulting.com/articles/pollarding.html

http://www.passionfortrees.co.uk/html/pollard.html

http://landscaping.about.com/cs/lazy...pollarding.htm

http://lists.tree-care.info/uktc/arc...2/msg05541.php

http://www.rutlandwater.org.uk/Pollarding.html

http://www.coppicing.com/

http://www.powen.freeserve.co.uk/Gui...pollarding.htm

http://www.orchardsedge.com/article....pollarding.jsp

http://www.au.gardenweb.com/forums/l...9063576.html?8

Thanks Dadpad,
I'm onto the links you posted and will read and digest them.
- thanks, I'll have a look around those links as well.
Bushmiller - forced growth.... I think that this is a common effect in all plantation - same age trees all growing at the same time rate mean they all are getting maximum light?

[quote=dadpad;374378]
Murray you should contact one of the NZ farm forestry organisations and get some advice on these. They could be worth around $100/150 per stem if form is good and properly managed for timber.quote]

Thanks for the advice. I appreciate the thought. There was talk the last harvest was worth about $20k gross. I think the nett was a lot, lot less than that but our accountant arranged for us to have a valuation done by a forestry consultant when we took the place over so we have a benchmark. He did the random thing suggested - very competent, comprehensive report. The value situation is not helped by the Regional Council having a "down" on wood fires. They like clean electricity - of which we do not have an endless supply. Recent discussion on the nuclear option has stirred up a frenzy. Maybe I'll knock over the trees and put up a big clean reactor. Anything on eBay?