Cutting the bottom branches on Fir trees?

[Bow Saw]

     In the past month or so I have been cutting the bottom branches on my fir trees, it is my understanding that this will help to make a better log. But as I was cutting today I asked myself if I was not doing this for nothing? I was thinking that if I get the wood lot cut by a wood cutter he will cut it all in tree length. So the work I am doing now will be 
wasted!

[Ianab]

To improve the quality of the log you need to remove those lower branches early in the tree's life. Then as the tree grows the later wood layed down on the trunk is clear timber with no knots, hence more valuable.

You also need to document the pruning so you can show the logs are of higher quality than normal unpruned logs, and market them as such. If they are just scaled and sold as normal logs your work is wasted, but the mill gets the bonus when they saw more high value clear timber than expected from your logs.

Lift pruning a mature tree will not gain you anything as the knots are already embedded in the trunk.

Ian

[SwampDonkey]

Be careful Bow Saw, pruning spruce and fir increases incidence of rot in the main stem. Be careful not to wound the trunk, leave a 1" stub and don't cut into that collar of the branches where they attach to the trunk. The best way to prune spruce and fir is grow them tight and do several thinnings as the bottom branches die. Too open and they will limb up again. Then you gotta hope you get a better price in the future than right now to justify all that work. It's fine to do it on a small acreage, kinda a hobby and good exercise. I don't want to discourage your efforts, but "I told ya so" at least. 

[Ron Scott]

Ditto! to what swamp said. Not to much advantage to pruning fir unless its a "hobby thing".

[Mooseherder]

It sure does make for a Park like setting.
Bow Saw has trimmed a few thousand trees and would have withdrawals if he had to stop.

This is one of us cleaning my saws at his place because they really needed it and I can't do it as well at the Camp.  They don't show how beautiful their place is.

 



Here is another looking the opposite direction.  Mom was letting my brother drive the Rhino.

 

[Clark]

I'd agree with SD on everything except leaving a stub.  On one hand you don't want to cut into the trunk itself, but rather leave the branch collar intact.  Leaving a stub keeps the saw away from the collar but also shoots you in the foot if you want to prune for better timber.  I'd say learn how to properly identify the branch collar and then cut as close as you think you can without cutting into it.

Clark

[SwampDonkey]

Going to be worst than shooting your foot when your trees start developing bole rot.

[Clark]

Going to be worst than shooting your foot when your trees start developing bole rot.

So presumably leaving a 1" stub will prevent bole rot?  Mooseherder should expect most of those trees to be cull by the time harvest arrives?  Just curious as I have no clue how leaving something behind would help prevent fungus from entering the tree.

Clark

[SwampDonkey]

Pruning whether a 1 inch stub or to the branch collar will increase the probability of rot in spruce and fir. It's just not done. I have a back yard full of pruned spruce my father trimmed up 30 years ago, all full of rot. 

[Mooseherder]

I'm gonna be upset if these rot.
At this rate only about hundred trees are getting trimmed every year.   Another 100 are getting space thinned.  The space thinning will continue as these were way too tight.
If I see some evidence of damage I'll stop before doing more trimming of lower branches.   

I leave about a quarter inch of stub or a tad bit less.  The trees from last years trimming looked healthy.  Time will tell.






My focus this year was on this side of the camp.  These Quaking Aspens were suspect and way too close to the camp.  I took down a dozen or so.  Only one didn't fall the direction it should have.

[sharp edge]

On white pine  been cutting them 1 foot long on the dead branches. Hoping they will rot quicker then collar can pinch them off. A long dead branch can wick a lot of water out of the trunk and wont rot. Don't know how this is working out , time will tell.

SE

[Clark]

Pruning whether a 1 inch stub or to the branch collar will increase the probability of rot in spruce and fir. It's just not done. I have a back yard full of pruned spruce my father trimmed up 30 years ago, all full of rot. 

That's kind of what I was thinking too.  Obviously pruning fir and spruce isn't an ideal proposition but if someone really wants to do it, I think we owe it to them to teach them how to do it correctly.  Soon you end up with people applying that advice to other species and they are really doing themselves a disservice. 

sharp edge - Prune those white pine right up to the branch collar, you're wasting your time if you don't.   Here's a link to help identify the branch collar.

mooseherder - It looks like you are mostly pruning dead branches so I wouldn't worry about it much.  Physiologically the tree should be fine but until the wound is healed over there is always a chance for fungus to enter.  Just follow good pruning practices (which it appears you are) and don't worry about the rest.

Clark

[Bow Saw]

Thank you all for responding to my inquiry about pruning fir trees.  Now for my next question;  How would you go about to document the cutting that is done to the wood, if I only trim an acre to an acre and a half out of one hundred plus acres per season?

[Mooseherder]

Thanks for that link Clark.  That'll help.
Yes, those were dead branches on the Fir and Spruce.

[Ianab]

Obviously different species and different climates / growth rates will have different effects.

As I'm not familiar with your trees or your climate our results may be very different and you should pay more attention to the local advice.

But - some actual dissections of how pruning 'should' work.

This is a slice through a 5yr old pine tree that had been lift pruned once, but thinned on the next round. I cut it in 1/2 to see what was actually going on inside. The branch scars are still clearly visible on the bark, and you can see the bulge where the whorl of branches were, but the wood being layed down from this point is totally clear of defects. The log is about 7" diameter at this point.



A section through a branch that was pruned just outside the collar and has healed over perfectly. You can see some discolouration down the branch, but the wood is still solid and is now sealed over which should prevent further rot.



Another knot on the other side hasn't healed over as cleanly and it's left a small cavity of bark and pitch. But it's still sealed and there is actually less decay in the branch stub.



Closeup of the 2nd branch.



Now these are very fast growing trees so they seal up the pruning wounds very quicly, these have grown over completely in approx 12 months. Your mileage may vary.

I do still wonder how much worse pruning off the suppressed and dieing branches is going to be, as opposed to letting them self prune and rot off naturally. It just seems that cleanly removing the branch and allowing the tree to heal quickly should be better than leaving a rotting stub that has to decay away before the bark can close over.

Removing larger branches from an open grown yard tree would certainly increase the possibility of rot getting in as it is going to take MUCH longer for the stub to close over. But removing dead or dieing branches in a closed over canopy situation, I cant see as being any where near as harmfull.

Cheers

Ian

[Bow Saw]

     Putting in my 1st practice picture of the pruning & thinning that was done to some fir trees on my woodlot......so please.....go easy on me
 

[pigman]

Bow Saw, I don't know anything about pruning, but you are good at picture posting and driving an ATV with a passenger on the back.

[Mooseherder]

Great pics Ianab and Bow Saw.

[Clark]

Ianab - Thanks for those great pictures.  That radiata pine is amazing stuff, what is the typical pruning and thinning treatment for those trees?  The forestry down in Aus. and NZ has always fascinated me.

Mooseherder - One problem with pruning the fir and spruce is that neither grows all that fast.  These radiata pine that Ianab is showing us are Olympic sprinters while the rest of us are running the three-legged race!  There is nothing bad about pruning the fir and spruce, especially if you are only taking off the dead branches.  As SwampDonkey has pointed out, the fungus will quickly take over either of these trees if given a chance so pruning is usually not even considered.

Another problem with pruning the F&S is that there aren't many products that the market demands for straight, clear F&S.  My grandmother is sitting on 200 cords of balsam fir that is running 30 cords/acre.  It would make great logs for a cabin but it can difficult to find someone willing to cut the good stuff with the bad.  Don't get me wrong, I wish I could see more stands of balsam like my grandmothers, but sometimes you can't get rid of it even when you need to.

Clark

[Ianab]

Ianab - Thanks for those great pictures.  That radiata pine is amazing stuff, what is the typical pruning and thinning treatment for those trees?  The forestry down in Aus. and NZ has always fascinated me.

The exact pruning and thinning would depend on the actual site, climate and soil types. The trees would normally be planted around 3-4m spacing, mostly to get an early canopy closure to supress weeds and encourage a taller form with suppressed lower branches.

The first prune would normally be after about 3 years. The tree would be 5 or 6m tall and would just be pruned from the ground, leaving 3 or 4 m of green crown, The trunk would be about 4" dia where the pruning stops.

The trees would be pruned 2 more times, maybe 5 and 7 years, or up to 10 years on a poorer site. That gives 6m of pruned trunk, again a 4" dia at the top, and 3 or 4m of green crown remaining.

Pruning is generally with hand tools and ladders. A big set of double acting loppers and a nice sharp hand saw for any bigger branches. Chainsaws can be used, but are not a lot faster than loppers, and more dangerous to the operator and the trees. If you are standing on top a a 4m ladder with one leg wrapped around the tree for stability, hand tools are actually easier.

At some point the extra stems are thinned, generally to waste unless it's an easy access site where the small stems could be harvested for posts or pulp. But it's low value stuff and is generally just left to rot. The inital planting would be around 700-1,000 stems per hectare, but it's thinned down to 250-350 actual crop trees. By the time you take out the double leaders, broken tops, animal damaged, bananas, and just runts you should be left with the best trees and if you have to take out a few 'good' ones to prevent overcrowding, so be it.

But all the silviculture work is completed in the first 7 -10 years, then the trees can just be left. Harvest would be 25-30 years for good sawlogs. The trees could be 30" dbh by then, and the pruned butt logs would have a 6" core of defect, the rest is clear timber.

A lot of work, but the end result is 2 or 3 times the return at harvest.

Ian