Kernels

I finally got the model working! The kernel looks good and its graph is pretty (below). I’ve used some iterative code to find the model’s stable population growth rate, stable stage distribution, and reproductive value vector. I have not used a very large matrix due to the computing limitations of my laptop, but I can easily transfer my code to a more powerful computer when it becomes necessary.

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DBH to Height

I’ve spent the last week making regressions for different data in R. Actually using R and manipulating data is quite easy. The hard part is trying to get good data. There are multiple years of data entered by multiple people at different times and in different ways. The result is a bit of a nightmare when it comes to using the data (and I have, in fact, had nightmares about it). There are some trees that have a diameter at breast height( DBH) but are only a foot high, there are some trees that have the same ID number as a different tree, and there are some trees that have simply gone missing. A big part of this summer will be finding if the funky data are from something being lost in conversion from PDF to Excel, or if there were errors recording data in the field.

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Some Direction

I was a little hazy on what I’d actually be doing this summer. Would I be helping someone else with her research? Would I be using data that was already collected? Or would I be messing around until I had the opportunity to head to Maine and Vermont to collect new data? It turns out I’m doing a little bit of each. There is an incredible amount of data being used for a matrix model that has been in the works longer than I’ve been at W&M, and I am helping sort through it, picking out funky pieces of data and marking them so they can be checked with the real trees when we take the trip to Maine. I am also using the current data to practice my modeling skills. One goal for the summer is having a functional model for the Maine data. I am using a statistical program, R, that is very different than Python ( the language I’ve used so far in my CS classes), and I spend a significant amount of time just trying to find proper syntax and functions for the things I want to do. Once more data is collected, there will be two years of data collected from the Vermont site, and I spend time this fall building a new model for a new set of data.

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