How about basal area increment?

Basal area increment is a good approach, and easily done in excel.

I would say tree ring-widths are as accurate as the person and equipment/microscope used. I think they can be very accurate. You could look into allometric growth equations to see if any exist for your species. If you wanted a rapid assessment DBH and allometric equations might be a good bet.

if you don't have a measuring system, a cheap (quick?) approach is using scanned images (2400DPI at least) of your samples and measure the rings using the CooRecorder/Cdendro suite.

http://www.cybis.se/forfun/dendro/index.htm

As Relena says, once you have the RW measurements, BAI is easy to calculate in Excel.

I agree with BAI

I agree with Rob and prefer the calculaion of BAI.

Therefore it would be helpful to have cores from more than one radius and averageing them.

For the calculation of biomass you additionally would need yearly resoluted values for the development of tree hight.

There is a a very allometric strong relationship between stem diameter and biomass for most woody plants. Many of these are published so you could easily calculate diameter increment and convert it to aboveground biomass. What species are you working with?

NB that I think there is the possibility of BAI having a positive age related trend bias. Forest ecologists often use BAI for assessing decreased productivity, but most BAI series I have seen are almost always positive, which in my mind may reflect an age related trend.

Tied in with allometric growth equations sounds like a useful approach. It might not be as "quick" as you would like thoguh

Well, basal area increment still does not represent biomass growth, although they are correlated. Once you have estimated (or measured) BAI increment you need to estimate also height increment to get biomass.

Core samples are very useful to calculate past basal area, but only in the case you have reached the stem pith, because stems are usually eccentric. When you have cores to the pith then you just calculate relative tree-ring width (TRW) increments so that you divide the actual TRW by the total sum of TRWs in the same core (coring direction). You also need to measure the current basal area and just multiply with these relative increments. This way you obtain past basal area with satisfying precision, because it is known (http://link.springer.com/article/10.2478/s13386-013-0152-3) that the relative increment is same around the stem circumference.

However, for heigth increment you will need some local height growth models, because the height growth is highly dependent on site (climate and soil) quality (http://link.springer.com/article/10.1007/s10342-013-0708-z), while basal area increment mosty on thinning regime.

Many thanks for your thorough insights.

The wood species I'm looking into is Mountain birch. I have no idea if applicable 'allometric growth equations' have been published for these or not (feel free to let me know if you do!) but I think the BAI is likely sufficient approach for starters. The keepers of tree gardens would not look kindly to some of the more laborious approaches... =)

I'm comparing some samples from the seeds of the same trees in grown northern and southern Finland, hence the need for the analysis. I'll also do some structural analysis comparison (ongoing) as there seem to be some differences in their cell wall and fiber properties.

You may find the equations in this paper useful.

SILVA FENNICA

Monographs 4 · 2005

The Finnish Society of Forest Science

The Finnish Forest Research Institute

Dimitris Zianis, Petteri Muukkonen, Raisa Mäkipää

and Maurizio Mencuccini

Biomass and Stem Volume Equations for Tree Species in Europe

I am agree with the suggestions of Michal for the calculation of BAI and height increment but for the calculation of annual biomass you will have to estimate one more parameter i.e. annual ring density or basic density of each annual ring either by x-ray densitometer or by mercury or water displacement method and finally annual biomass (gm/year) will be calculated as BAI x Height increment x annual ring density

Well, one would EXPECT annually varying biomass growth, especially in environments limited by few environmental factors, such as the high arctic. Generally, one could compute the basal area increment from annual ring width, and then apply an allometric formula for that tree species (from that environment) to reach annually resolved biomass. C is about 47-49% of the biomass. See example in Wilmking et al. 2006 Effect of treeline advance on C storage... Journal of Geophys. Research. many greetings

Martin

As an estimate, BAI from breast height is good; however, a relatively recent set of papers on the growth of large, old-trees suggests that BAI at breast height is a poor estimate of whole tree growth. Here are those references:

Sillett, S.C., R. Van Pelt, G.W. Koch, A.R. Ambrose, A.L. Carroll, M.E. Antoine, and B.M. Mifsud. 2010. Increasing wood production through old age in tall trees. Forest Ecology and Management 259: 976 – 994.

Stephenson, N.L. and 24 other authors. 2014. Rate of tree carbon accumulation increases continuously with tree size. Nature 507: 90 - 93.

BAI and volume increments are often used to this end. For example, have a look:

doi: 10.1111/j.1365-2486.2008.01570.x

doi: 10.1051/forest/2010031

and also:

http://link.springer.com/article/10.1007/s10021-013-9719-3

You can find useful functions in dplR package in R for your task...

Antti, what kind of material do you have at hand? Did you cut whole trees or did you collect increment cores only?

In case you cut trees, I would calculate BAI for stem discs collected at different tree heights, i.e.: performing a stem analysis. Since it is known that (annual) growth allocation varies along the stem, for example as a result of weather fluctuations (e.g. http://www.nrcresearchpress.com/doi/abs/10.1139/x2012-046#.Uzw1O62Sxfd), a stem analysis will result in more accurate estimates of biomass as compared to the method based on an allometric formula and BAI calculated at breast height.

Best regards,

Ernst

I'm little short on material / samples and limited to work only with single stem disk per trunk. My samples are, however, taken closer to knee than breast height... having still diameters less than 40 mm after 20 years.

With samples from few different growth areas (nordic fell top, nordic river valley and green southern forest) for trees grown from seeds that originate from specific sources (with also some variation in growth area) we hope to get some preliminary idea on the growth factors and structural properties of wood - i.e. genetic and environmental impact.

Delivering the whole tree from the arctic to lab would have been nice but rather laborious and costly task. Luckily, the biomass growth is not the key thing here and I think we'll manage with less-than-perfect estimates quite well.

Once more many thanks to all of you who have provided such excellent advice for me. This is all fairly new to me as my background is strongly in the world of engineering and most wood fibers I have ever analyzed prior to this have come in the forms of pulp or paper... =)

We used regression equations between basal area or basal diameter and biomass. We had the posibility of measure biomass on logged trees of different sizes and then construct the regression model. You can see the method we used in the article:

J A Alvarez, P E Villagra, R Villalba, M A Cony, M Alberto. Woody productivity of Prosopis flexuosa D.C. woodlands in the central Monte: Influence of population structure and tree-growth habit. Journal of Arid Environments (Impact Factor: 1.77). 01/2011; 75. DOI:10.1016/j.jaridenv.2010.09.003

Best wishes

Pablo

regression equations between basal area and biomass can be used . We had the posibility of measure biomass on logged trees of different sizes and then construct the regression model

You can also use Height, diameter and specific gravity for calculating biomass.