whole tree harvesting

[240b]

In regards to whole tree harvesting, which is very common in this area and makes up half of my jobs. does any one know of and any studies which show it having an negitive impact on soil health/productivy  I've heard so many conflicting opinions about this and Iam intrested in seeing some data(if any exists).  One group (foresters) wants to see very last twig loaded and headed to the mill (biomass plant) and the other thinks most of the top should be left were it falls.  Anybody have anything?

[Tom]

Most of the Foresters I've spoken with, leave the fines in the woods.   The big argument generally comes from the Pine Straw harvest, not the chipping operation.  Even if you chipped everything, you would probably leave enough fines  (twigs and leaves) to add nutrients back to the soil. 

[WDH]

Research in Germany has shown that if all the biomass is removed, like in harvesting all the limbs and twigs constantly for firewood, that after many years, year in and year out, nutrients loss results in a loss of soil productivity and tree growth.  However, this is intense removal.

Whole tree chipping once every 40 years or so may have a small impact.  You would have to do it over and over again for many decades and centuries to make a large impact, and that is not likely to happen. 

There are not many nutrients tied up in the wood of a tree.  The nutrients are tied up in the leaves/needles, and these fall to the forest floor and are recycled.  That is the issue with repeated harvests of pine straw. 

Whole tree chipping using a flail to remove limbs and leaves/needles would not a significant concern.  Again, it is the constant removal of the leaves, needles, and twigs that mounts up to cause a problem. 

[Ron Wenrich]

Here's a study:

http://smallwoodnews.com/Docs/PDF/Utilization/LoggingResidueReport.pdf

If you put "whole tree chipping nutrient loss" into a search engine, you'll get a lot more.

It seems that the ones I scanned say that there is nutrient loss if you take the fines and the foliage.  But, each site is different.  Intensity and time of year also have an impact. 

[240b]

Thank you for the input.  The smallwoodnews.com paper was a good place to start.  It appears that this issue is typical of so many things in forestry- nothing is black and white.  Each site and objective is different- in  the end some sort of happy medium is most likey the right thing to do.

[ncsuclell]

NC State was doing a long-term research project that was wrapping up when I was there (in 2006).  It was being conducted on some IP land in NC.  The study started 30-40 years ago and was looking at a few different things.  One of those was whole tree harvest vs. taditional harvests.  They measured the current forest conditions including tree hts, BA, diameters, etc.  Then they harvested different sites using each method of harvest and recorded the volumes from each. 

After the cuts were made they replanted each site with loblolly.  Each site had a different harvest method, site prep, and some sites were herbicided and some were not.  They were looking at a couple of different aspects of forest practices and their effects on the next generation.

I did an undergraduate study poster on the effects of the litter fall that was collected one year before the final harvest in 2006 - 07.  I noticed no significant differences in the litter accumultion from similar sites where the only difference was the harvest method.  That is important to note since trees often put a lot of nutrients into their leaves and that is where food is made.

I think the professor in charge of that was Dr. Lee Allen with the NCSU School of Forestry and Nat. Resources.  He was also my Silviculture professor and the Director for the Forest Nutrition Coopertive.  Dr. Allen would know more about the over all results of the study.  I only focused on litter fall.

You can find is email on the College's website http://cnr.ncsu.edu/fer/  Just look under Faculty and Staff.  His email should be on there.  Or if you would like I could contact him with your question.  Just let me know.

[Ron Scott]

The US Forest Service and the Canadian Forestry Service has done a number of Soil Poductivity studies in regards to logging methods on different land and soil types around the country. I was in charge of implementing such a study with Research on the Huron National Forest when I worked on the Huron-Manistee National Forests in northern lower Michigan.

As Ron W said, there are different impacts on different ecological land types and soil types. Total tree harvesting was not normally not allowed on the dry sterile, mesic soils of the Huron Forest. The number of repetitions of such a logging practice on a site was also a factor as stated above.

[Woolywolf]

I remember having this question on my silviculture exam. Like 240b said, this isn't a black or white issue. It depends on the the species; it depends on the time of year; it depends on the nutrient you're talking about; it depends on the soils; it depends on the time frame; it depends on who you're working for or who's funding the study  .   

[240b]

that is the conclusion I've come up with.

[pappy19]

One thing I have found with whole tree removal is that the damage to soil and leave trees is much less as the branches seem to hold the trunk from compaction and associated gouging of the skid trail. Also, even without chipping the entire tree and one does all of the log trimming at one landing, you could chip the slash or burn depending and all of the slash is in one location. Makes alot more sense to me than trying to pile and burn out in the leave stand.

[Rocky_Ranger]

Weyerhaeuser down here whole tree harvests and aerial applies prilled fertilizer with SEAT's.  Now that is taking care of business.  They normally use our helibase area at the airport and so the Forest Service gets blamed for herbiciding the forest.  As was mentioned earlier, a lot depends on the circumstances - some of the whole tree chipping we've done leaves so much needle fall on the site I doubt any change will occur on productivity for several entries.  Even whole tree chipping leaves material non usable for chips, we normally have the skidders relocate that material back out on the skid trails.  We follow up with a burn 6 mos to a year afterward to release nitrogen back into the soil.

[chevytaHOE5674]

One thing I have found with whole tree removal is that the damage to soil and leave trees is much less

I've noticed the opposite. UP here generally the machines drive over the tops and slash so that they hardly even touch the soil they just drive on the "mat" of debris. When they do whole tree harvesting operations the slash is removed, therefor the machines are forced to drive directly on the soil. Noticed the last timber sale I inspected (whole tree harvest) that there was much more impact on the soil compared to driving over the tops and slash.

[thecfarm]

240b,update your profile so I know where "in this area" is. I have no idea,but some outfits do a little both around here.I went on  school trip and they was doing both.I think most of the guys that I see around here do logs and pulp,no chips.But 2-3 hours north is differant.Can't be much money in chips because not many are doing it here.I'm only 15 minutes from a bio mass plant and don't see hardly any chipping operations.I see alot of trucks coming form the North.

[pappy19]

One thing I have found with whole tree removal is that the damage to soil and leave trees is much less

I've noticed the opposite. UP here generally the machines drive over the tops and slash so that they hardly even touch the soil they just drive on the "mat" of debris. When they do whole tree harvesting operations the slash is removed, therefor the machines are forced to drive directly on the soil. Noticed the last timber sale I inspected (whole tree harvest) that there was much more impact on the soil compared to driving over the tops and slash.

If that's the case, then what do they do with the slash after it is run over so many times?? Do they pile it after harvest and then burn or what? Again, if skid trails are "loggers" choice, the skidders generally take a different trail from each tree, or the shortest distance to the landing. This method usually makes for a limited effect on soil compaction. Soil scarification isn't bad, but compaction is very detrimental to recovery and adds to water/erosion velocity.

[chevytaHOE5674]

They leave the slash in the woods after its been run over on normal log/pulp harvesting. It rots away and adds to the soil over time.

[thecfarm]

pappy,I had my lot cut and he did a nice job.Did not take the shortest route or make a mess with the slash.There was some places they did not run over the slash.A few more cut with a chainsaw will lay the brush down on to the ground.He stayed to the main trails.Some are going to forwarder like what he used.The lot next to me was cut off with a skidder.I would of kicked him out if they would of done what they did on his  land.Run over small marketable trees and bark up others and just leave them.This guy use to run a skidder all the time.He does have one for the hard places,he used it on my land.I watched him cut for 20 years and every lot that I saw him cut looked good.I don't what you to think skidders make a mess,operators make the mess.A good,clean,pretty job can be done.I told the guy that cut my lot I would kick his ass of my land if he made a mess and he knew I meant it.I checked on him daily,not that I needed too.When I went to ask him about cutting on my land,he was on paper company land.He was moving brush,by hand,to make a road for the forwarder to ride on so it would not sink into the soft ground so much when I saw him.He had no idea I was there.We need more like him.
Any trees that are cut for logs,the slash is left in the woods.Around here I have not ever heard of any burning of the brush in the woods.

[woodtroll]

Burning of the slash/ brush is used in the west. The slash will not rot quickly and turns into a fire hazard. So, to mitigate the slash needs to be disposed of, chipped ($$), piled and burned ($) or lopped and scattered with a possible burn the next year or two.

With the different forest types and conditions no one way works for all of us.

[Rocky_Ranger]

Not just the West, we burn about 30,000 acres/year here and maybe 25% of that is post harvest burns.  Everything from seed trees to first and mature thinnings.  Sure makes the place clean up good.

[ncsuclell]

I've noticed the opposite. UP here generally the machines drive over the tops and slash so that they hardly even touch the soil they just drive on the "mat" of debris. When they do whole tree harvesting operations the slash is removed, therefor the machines are forced to drive directly on the soil. Noticed the last timber sale I inspected (whole tree harvest) that there was much more impact on the soil compared to driving over the tops and slash.

In my dealings with loggers (mostly in the south) everyday I inspect I have to ask to please take the slash in the woods and spread it on the trails.  But they give me a sad story that it costs them in fuel and time to do so.  I usually get a halfA$$ed job of it.  Most of them would rather leave it on the deck.  Down here in FL the problem with not taking the slash and spreading it on the trails is that if it rains, the is shut down for a day or more b/c of rutts.  If the logger had taken the time when it was dry to spread the slash on the trails it helps prevent that.  And doesn't help to fill in the rutts with slash after you have a 2-3 ft hole/ditch in the ground.

[Ron Scott]

That's one of the reasons why I don't allow tree length logging on most of my jobs.