projecting growth/acre in hardwoods

[woodtroll]

Hey all you technical foresters
How would you project growth, in volume (BDFT), per year, per acre?

[bigtreesinwa]

My suggestion would be to go to the Web Soil Survey. It's a service sponsored by the NRCS and you can get to it by going to nrcs.gov and clicking on soils.

Locate your parcel on the map, and select a timber report. The report will have an estimate of how many cubic feet a year your soil is estimated to grow. You can convert cubic feet to board feet or cords of wood depending on your purpose.

Let me know if you need more specific info on finding the report.

[clearcut]

I project forest growth and yield using a computer model specific to the area where the stand is growing, applying the model to carefully collected inventory data.

I have also used Stand Table Projection. Build a table by species and diameter class, estimate average periodic growth  from increment cores, and apply to the table. You are estimating how many trees in the current diameter class will move into the next diameter class.

Yield Tables have been developed for many places that predict stand volume for various ages using site index. Some tables adjust for stand density.

The Web Soil Survey method mentioned by bigtreesinwa gives a reasonable estimate with minimal cost and effort and provides a check on the other methods. It tells you what the site is capable of if fully stocked. The other methods adjust for current stocking.

[woodtroll]

The info from soil surveys for my area are inaccurate. The current online forest productivity data does not have any growth volume listed just site index.
The data from the soil survey is what got me wondering any way. Reports of 200-500bdft/ac/yr in my area is just wrong. I wish I knew their methodology. I would love to grow that much.

I like clearcut's method of data and increment sampling.

[bigtreesinwa]

How did you figure?

I get 157 - 166 cubic feet per year in my area. One cubic food of wood is equal to 5.5 board feet, so it comes back around 600 - 700 board feet per year. I haven't had a chance to compare these values to my growth rates but I'd guess it's reasonably close. The big assumption is the number are for an optimally stocked forest. Half of my forest is optimally stocked and about half is underoptimally stocked.

As other's mentioned, the Web Soil Survey is a quick and dirty method. I'll look into the methods suggested by others since I'd like to pin down the growth rate as accurately as possible.

[woodtroll]

Different forest type in Washington. Especially west coast.

 I checked the numbers. Tried to replicate result.
In the central hard woods, 200 bdft/ac/yr, 40 years, 8000 feet to the acre. It just is not there. The problem comes when foresters tell a landowner these numbers and it does not show up.
It is critical for good forestry to know what you can produce.
Thats why I am looking for suggestions.

[bigtreesinwa]

You really have me thinking now. I'm an engineer by trade and make models of things in my professional work so having a good model for my timberland would make good sense. I'll look more into it and post here when I've found a good solution. It'll be a good six months or so.

[pappy19]

I had to calculate basic stand site index's on 360,000 acres in Valley County, Idaho, mostly on old Boise Cascade timber lands. I decided that the only fair way was to find the largest, healthiest trees by species randomly across a plot and take an increment boring. Then I measured height and diameter combined with age and developed a site index for that plot of land. Yes, it was biased as my thought was to see what that site could produce. This effort was to classify lands as good, average and poor for taxing purposes.

To my way of thinking a soil type, slope orientation, average moisture, number of stems per acre, species mix, etc. are all components of that site. If a plot of land can produce X amount of board feet per acre per year say for Ponderosa Pine, and XX amount of board feet per acre per year for Grand Fir, then the maximum footage makes the site good. One must develop and guide for what is good, average or poor. It will obviously vary from area to area.

[woodtroll]

I do not mind using site index. It is a way to rate productivity of a site. Height in how many years. It is easy, simple.
But volume is different. The more species on a site the more variables. Diameter growth plus increase in merchantable height.
I feel comfortable about a ten year projection.
Based on incremental growth.
Not much more.

[pappy19]

I don't have a problem with that, but site index should reflect the very best that site can produce, regardless of species, except for volume of wood produced compaired to any other site. It all depends upon choosing the tree that is the most dominant on the site, that's the key.

[woodtroll]

I agree with that.

[WDH]

I subscribe to the increment core method.

[Clark]

woodtroll - Where are you at?  Having a location in your profile might allow some guys working with the same forest type to simply give you some numbers.

A simple Google search of "hardwoods growth projection" retrieved this article.  I didn't have the time to look all the way through it, but it seemed pretty good. You might also want to check out Treesearch, a repository of research articles by the Forest Service.

bigtreesinwa - You don't have to rub it in that you have land in some of the most productive conifer forest in the world!  It's a whole different ball game back east, slower growth rates and more than 5 species!

Clark

[bigtreesinwa]

bigtreesinwa - You don't have to rub it in that you have land in some of the most productive conifer forest in the world!  It's a whole different ball game back east, slower growth rates and more than 5 species!

What? You guys don't have 38" (DBH) Douglas-fir, 36" (DBH) Bigleaf Maple, and 48" (DBH) Western Redcedar on your properties?

Alas, I'm very forunate to live in a place where trees love to grow. I went camping last spring, and at the campsite was a big tree. It was so big I dug out my tape measure to measure it and it turned out to be around 55 - 59" in diameter at breast height. That was some big tree! I figure mine increase in diameter by about 3/8 - 1/2 inch per year, so mine will be that big someday in the not too distant future as well.

The downside is I have to deal with Seattle weather, which is rain, rain, rain, rain. It's not just the trees that grow, the underbrush grows really well too and makes our forests thick and hard to walk through. A lot of times I look at eastern Washington forests and see how clean they look and think that'd sure be nice.

Greg

[clearcut]

Site index is best determined using a method as close as possible to the one used by the developers of the site index curve / equation that you are using. While most often is the the dominant tree, free to grow throughout its life time (confirmed by the increment core), I have seen methods such as the 5 or 10 tallest trees in the stand, the tallest trees on an inventory plot, and such. You generally have to go back to the original publication to get the method.

In general, in temperate forests, and for most species - height growth is largely a function of species and site quality and is weakly influenced by density. Diameter growth is largely a function of species and density, with site quality having a much lesser impact.

For most places and species in the US, the Forest Service and/or the state land grant university have developed model the predict forest growth and yield. Some are straightforward, easy to use and easy to understand, others are ... well let's just say that you have to decide whether the potential information gained is worth climbing a very steep learning curve.

Your local Cooperative Extension forester may be able to point you in the right direction for your location.

[SwampDonkey]

The downside is I have to deal with Seattle weather, which is rain, rain, rain, rain. It's not just the trees that grow, the underbrush grows really well too and makes our forests thick and hard to walk through.

Yeah it was nice and wet in the Charlottes to, but where the wood was growing best the undergrowth was next to nil. Mostly moss, very scattered false azalea, , huckleberry and devil's club. No hardwood except a grove of alder on an old slide, usually over taken by Sitka spruce in time. Aside from the rain and slick side hills, could spoil a man.


Growth in my area, where the best sites are for New Brunswick we get around 0.6 maybe 0.8 cord/acre/year. The 0.8 is almost mythical. and I've never seen the mythical 1 cord per acre here, if we did than we would be getting a lot more than 26 cord per acre from harvests at maturity. Cedar can have higher volume, so can some hardwood because they are more shade tolerant and growth tighter. But they took 180 and 100 years to get there respectively. So yes, I have seen 60 cord/acre on cedar and 40 cord/acre on rock maple sites. And most those exceptional rock maple sites are growing potatoes now, so don't come looking.

[bigtreesinwa]

The downside is I have to deal with Seattle weather, which is rain, rain, rain, rain. It's not just the trees that grow, the underbrush grows really well too and makes our forests thick and hard to walk through.

Yeah it was nice and wet in the Charlottes to, but where the wood was growing best the undergrowth was next to nil. Mostly moss, very scattered false azalea, , huckleberry and devil's club. No hardwood except a grove of alder on an old slide, usually over taken by Sitka spruce in time. Aside from the rain and slick side hills, could spoil a man.

Where's the Charlottes? Sound nice!

[SwampDonkey]

Off the NW coast of BC, north or Vancouver Island, a little south of Alaska border. But big trees.



Yup, me on Elizabeth Island in the Queen Charlotte Islands. Looks trashy there because of being on the edge of a cut block after the site had been harvested 2 years before. A few alder along the road coming along, can see leaves in lower left.

[pappy19]

One interesting side note on release of old growth trees. I was working as a forester for the Idaho Department of Lands in McCall, Idaho and we were thinning some real old growth Ponderosa Pine, probably averaged 250-300 years old. A consinsus was made to cut all of the co-dominants and leave the dominants for seed trees. We did just that. Some of the clusters of trees had 7-8 nice old growth with the dominant tree standing above all of the others. A few years after we did the cut, I went back just for fun and did some additional core samples. Every single dominant old growth leave tree released and doubled or trippled it's growth rings after the cut. I was shocked. Just goes to show you on a good site, a healthy dominant tree will just keep on growing.

[woodtroll]

I have been going over these posts and considering the answers to the question.  I am trying to hammer home how I will do what is a critical part of managing a forest.
I need to be able to tell a landowner "your woods should realistically produce this much volume in 10 years or even 20 years." Not under fully stocked perfect stand conditions.  Most likely their woods are not in that condition.
I have talked with extension foresters, district foresters, ect,they start to glaze over once you get away from the charts and ask how the charts were made.  I have looked at soil books that is what started this problem.  At first I used the numbers. 200bdft/ac/yr as high as 500bdft/ac/yr. But these soils and stands were not producing that.

Landowners were regularly told they can have another harvest in fifteen years. Fifteen years later it was not there, a forester sold them a load of you know what, to sell their timber. I do not want to be that forester.

Site index tells me what a stand can do. Dominant trees, height growth over time. That does not tell volume growth in X number of years. In the the central hardwoods you can't use total tree height for accurate volume estimates. It is merchantable height that counts. What the logger will take, and the mill pay for. There is a lot of variability here.

So I will give what I have come up with for my area. I do appreciate the feed back.

My cruises are variable plot. First tree sampled is always north. It gets measured and if merchantable, increment bored. All trees are measured dbh, merchetable height and class or defect. 
Then the data is ran through a cruise program that averages the growth of the sampled trees and uses that for a projected tree dbh. That is used to determine future volume.  Time frames are kept short. Twenty years would be pushing it. Merchantable height is kept at the original tallied height. Some trees would increase others not at all. This is the rough of it.

Swampdonkey, nice tree, I could handle a few of them in my hills.