Why tree ranges are different sizes

The curve indicates that there are many small diameter trees around 14 inches, a group of large trees around 32 inches, and a smattering of trees with diameters over 50 inches. Do the groupings indicate different age cohorts? Is the stand approaching an old-growth condition? Looking more closely at the data, note that the small trees are shade tolerant species, and the less tolerant Douglas-fir tends to be in the larger size classes.

What might that tell you? If that were not the case, the Smokies would probably have far fewer volume records and national champions. However, that does not account for the abundance of height records in second growth areas of the park or the unparalleled growth rates in the park. Red maple, black birch, black locust, sassafras, sycamore, tuliptree, bitternut hickory, white basswood, and cucumbertree all reach record heights in the Smokies in second growth forests.

In the Smokies, all of those species are towards the southern end of their range, and some of them are close to the edge of their range. Species are not uniform entities; populations adapt to local conditions, so a population at the edge of the range can be just as well adapted to its habitat as a population at the center of the range.

Another complicating factor with this question is that the ability of a mature individual to grow well may not be well correlated with the species ability to reproduce in the area. For instance, a tree could flourish on a site where temperatures are never warm enough at the appropriate time of year to trigger germination of seeds. If that relationship were not weak, people could not plant trees outside of their native ranges and have them survive.

Several other factors probably weaken the correlation between position in range and maximum size, but I'm not familiar with them. I thought you question was interesting, and enjoyed thinking through why our data does not support that conclusion. What I see is the geographical range is simply where the tree will grow and reproduce. The shape or size of the range doesn't seem to me to have much to do with how common the species is in a particular area, nor how big a particular species will grow in an area.

The geographic center of the continental US is somewhere in Kansas I believe. This doesn't mean that the densest population of people is found in Kansas. The densest population of a tree species may be in one little corner of its range, with a broad area extending from that pocket like a tail on a comet.

Big trees are not even necessarily found where the species populations are the highest. Individual trees grow tallest in areas with a good climatic conditions and good soils. The best area for the tallest trees for a particular species could be anywhere within its range. In the rest of the range the population is reproducing -just not growing as tall.

I think it is generally fair to say that trees tend to be taller near their southern limits of their range - a lattitudinal trend -provided growing conditions are favorable, and secondary pockets of tall trees grow where beneficial localized soil and climatic conditions outweigh latitude in determining tree height.

I also do not see that competition from other tree species, climatic change, and similar edge of range effects are directly related to how tall a tree might grow.

These factors may impact how many of the species is found in that area, but its impact on the height of individual trees is problematic. Trees at the edge of their range, as Jess says, may be as well adapted to their local conditions as are trees in the center of their range. Things that affect how tall a tree grows may not be the same as factors that determine whether the general population of the species is high, low, diminishing, or increasing in a particular area.

I also want to add to Jess's comments that the tallest eastern white pines will soon be just miles from its southern range limit in GA.

Once you surpass a 25 Container size, shrubs and evergreens measure by height in inches or feet , and trees measure in caliper. Caliper is the measurement of the diameter of a tree trunk, in inches. These trees are planted as babies in farm fields and grown to more mature sizes. A homeowner is likely able to transport a smaller tree from 1. We recommend delivery beyond that size. If you want instant gratification, then you will likely encounter this additional note about about field-grown plants.

They've been sitting in the ground for years, so they are acclimated to their environment on the farm. All plants react differently to harvesting - having their roots cut. Harvest windows and dig times directly impacts the availability of mature trees, shrubs, and evergreens. Plants are living things and they all react differently to harvesting at certain times of the year.

For example, Birch and Oak trees only tolerate a spring harvest. We harvest as many as possible, then that's it until next year. Maples on the other hand are a popular tree that will harvest well in spring and fall. The "best" looking plants are tagged in the order in which we receive them - first come, first serve. There are even larger caliper trees in our inventory, such as 6. For years, these larger trees occupy valuable space and resources and receive professional care.

Larger trees have much larger root masses and are significantly heavier. They require larger machinery and more labor to harvest and transplant. To put this into perspective, the weight of a 1. Nursery Stock: Heights Shrubs and evergreens that are larger than a 25 container measure by height - inches or feet.

The concept is the same as our discussion about trees and caliper size above. Since they're not the same form as typical trees a trunk and canopy up top , field-grown evergreens and shrubs are measured by their height. The largest percentage of tree inventory grows in single stem form.