## Tree interactions and individual-based modelling

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Many scientific papers deal with aspects of plant interactions including competition and facilitation. It is very likely that plant interactions play an important role in structuring our ecosystems and this is indeed a prolific research field that has kept many researchers busy for the last hundred years. In the absence of a deeper understanding of… Continue reading Tree interactions and individual-based modelling

## Behind the paper “Do large trees tend towards high species mingling?”

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It often occurred to me that it is a pity to be able to read finished research papers only. As we all know, they have to be very concise and can only report a selection of the most positive outcomes of everybody’s research. However, this is only the tip of the iceberg, isn’t it? There… Continue reading Behind the paper “Do large trees tend towards high species mingling?”

## Agree to disagree

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In one of my previous posts in this blog I have talked about research into human tree selection behaviour. Since the previous post was published we have learned new things, which highlighted how complex and fascinating this research is. Experience is for example a term that often comes up in the context of human resources.… Continue reading Agree to disagree

## Spatial species mingling

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$M_i^{(k)} = \frac{1}{k}\sum_{j = 1}^k \textbf{1}(species_i \ne species_j)$ j denotes the jth nearest neighbour of plant i. The expression 1(A) = 1, if condition A is true, otherwise 1(A) = 0. In principle, k can take any number and can also vary between plants of the same population or research plot.  However, for convenience k… Continue reading Spatial species mingling

## Basal area in larger trees and the growth compensation point

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${\LARGE BAL_i(t) = G(t) \cdot (1 – p_i(t))}$ with ${\LARGE p_i(t) = \frac{1}{G(t)} \sum\limits_{\leq g_i(t)} g_i(t)}$ What does it mean? The formula quantifies the sum of the basal areas of all trees that are larger or equal in basal area compared to that of a given tree i at time t. It is the complement value… Continue reading Basal area in larger trees and the growth compensation point

## The Chapman-Richards growth function

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${\LARGE y(t) =y_\text{max} [1 – e^{-kt}]^p}$   What does it mean? Growth functions in general describe the change in size of an individual or population with time (Burkhart and Tomé, 2012). Assume that $y(t)$ is a tree growth variable, e.g. tree total height or tree volume, and  $y_\text{max}$ is the maximum value this growth variable can… Continue reading The Chapman-Richards growth function

## Statistical consultation work at universities

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As part of my responsibilities I manage a statistical consultation unit in my Chair at Umeå and also take care of a university-wide Centre for consultation. SLU has in fact a good centrally organised and paid consultation service with dedicated staff. Every major campus at Umeå, Ultuna and Alnarp has a unit supporting students and… Continue reading Statistical consultation work at universities

## Open access for public data – Reality or wishful thinking?

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Terms like open source software, open access journals and public data have recently been much discussed in scientific communities and are in fact buzzwords. In the last few months I happened to get involved in issues of data transparency and of the availability of raw data. As part of this involvement I had to learn… Continue reading Open access for public data – Reality or wishful thinking?

## Can’t see the wood for the trees – The journey of mathematical forestry

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Today I am going to take you on a journey, the journey of mathematical forestry, which is also a bit of my own journey. When state-organised forestry was set up in different parts of Europe around 1750 the pioneers in this new subject area must have looked at vast areas of partly untouched (similar to… Continue reading Can’t see the wood for the trees – The journey of mathematical forestry

## Scientific programming – Is this really necessary and important?

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Basic modules in scientific computing used to be included in forest science degree programmes. For a number of years they seem to have disappeared in many countries, I am not sure why. Perhaps this has something to do with Bologna and such key-skill modules didn’t fit in any longer? This seems odd as many research… Continue reading Scientific programming – Is this really necessary and important?