Posted by Rachel on October 14, 2004

Q: Hello there! I just had a quick question about Scotch pines. I understand that they grow better in dry areas due to their preference for well drained soil, however I had a more specific question about their diameter. I noticed that the Scotch pines further inland are greater in diameter due to their more vigourous growth on account of the well drained soil however is there any other reason for this? Could it be do to the root system as well, the trees with the greater diameter have larger root systems which can tap into more limited water sources? I was curious since the ones by the water had smaller diameters so I thought it might have had something to do with water uptake. So what I'm really trying to say is tree diameter related to water uptake? I've been researching it but I haven't had any real luck yet. Thanks so much!

A: I'm impressed with your observational skills! The Scots (or Scotch) Pines, Pinus sylvestris, are not native pines but are very vigorous trees and tend to do well in many areas of North America. I could have used a bit more information about where you're located since I can't tell if you're referring to inland areas away from salt or fresh water. I'm going to assume that you are referring to being inland from saltwater - hope I'm right.

When trees grow in optimal ( best possible) conditions, they grow more quickly, are less prone to disease, and definitely become larger than others in less desirable areas. The difference in tree diameter you're seeing is probably due to the fact that the inland trees are growing in areas where conditions are better suited to their needs than those on the coast. The trees growing near the water are probably growing in marginal (less optimal) conditions and are therefore not growing as quickly.

Although each kind of plant has specific conditions that it is adapted for, their seeds do not necessarily begin growth in the best possible areas. A seed that begins life in a less-than-optimal piece of soil may die rather quickly or although it may live, only grow poorly. Of course there are all kinds of degrees of good and bad growth between the best growth possible and no growth at all. You may even notice that flowers that your mom or dad plant around your home seem to grow in one area of the yard better than another - this is what is happening with trees too. Keep in mind too that there are all kinds of factors that influence how well a tree grows and the soil is only one of them; humidity, temperature, pH (acidic or basic), sunlight, rainfall and many other factors all affect plants.

Hope this has helped. Keep up the good observations.

John Wiessinger ( October 15, 2004)