Forestry questions

[cooperhill]

1.Krummholz - this was discussed on a recent thread in the Trip Reports section. What is the main reason for the trees being so small? I have heard it is the short growing season (i.e. time when the tree can produce new growth). Or is it the elevation? or other?

2. What is a Montane zone? is it the same as a Boreal zone?

Thanks!

 

[raftingguy]

1. The short growing season is part of the reason for the stunted growth, but you'll find that the height of the krumholtz is about the depth of the average snowpack. The snow helps protect the trees from the harsh winter elements.

2. No idea here, I will defer to others.

 

[NYBRAD]

The trees are shorter for a few other reasons as well. Mineral soils found at lower elevations become organic soils above around 4000 ft and very thin .You lose the Red Spuce and enter mainly balsam fir and black spruce. Branches never really get to develop because of being repeatedly killed back by blowing ice. Fog also reduces photosynthetic rates.

 

[MichaelJ]

Another factor in play is rime ice and exposure to wind. At almost-upper elevations you'll see trees with one side almost dead or broken off. That's the side facing into the prevailing wind, and at an elevation that's generally fogged over and collecting rime ice. As the ice weighs the branches down on that side, the wind comes in and breaks them off.

The higher you go, the more this affects you, and so to survive you just adapt and don't grow as tall.
8)

 

[David Metsky]

Here's some info on "Montane Zone":

From Ranier
Ecology from BC
Yosemite

Never heard in used here in the northeast, but who knows?

-dave-

 

[spencer]

Elevation is not as directly involved as are the conditions often found at those high elevations. Think of the cols between summits that revert to trees proper even though they are at similar elevations.

MichaelJ refers to "flagging"

As Dr. D said in the other post, the trees exhibit a different strategy for survivial by growing horizontally rather than vertically. Spruce and fir (most trees for that matter) grow tall and relatively straight to outcompete each other for resources. In the krummholz zones, they don't need to grow vertically to outcompete each other. Rather, they have to hold on the longest.

Something I often notice about the krummholz is the clumping nature of both the spruce and fir. While I haven't found the primary literature to back this up (nor have I looked that hard) it seems to me that individual plants grow in clumps together to help each other. They hold an already very thin soil layer intact and offer some windbreak for each other. It's a study I'd like to do someday...

spencer

 

[el-bagr]

montane vs boreal: montane refers to the biogeographic zone of upland (mountain) slopes below treeline; boreal refers to the biogeographic zone of northern forests. Montane and boreal are thus conceptually distinct -- you could have a montane area in Pennsylvania that is not boreal, while much of northern Quebec is boreal but not montane. Practically speaking, in our neck of the woods, these two concepts refer to similar terrain, leading to frequently interchangeable use.

Spencer, I've read a few studies that addressed that issue -- tree islands in the alpine zone. Some theorize that younger trees are recruited behind the windbreak of older trees, causing the island to elongate -- while the windward trees are more exposed and may die. This leads to a propagation or traveling of the island. (Similar in concept to fir waves.)

edit to add: see, e.g., Harry White, "Tree islands in the alpine zone"

 

[Puck]

I just read the book Northwoods. by Peter Marchandhttp://amcstore.outdoors.org/AB1805000/showdetl.cfm/DID/8/Product_ID/274/CATID/19

He deals with you question regarding krumholtz. In fact it was the bases for his Phd research.

All the answers given so far in this thread are discussed.

It is a good read.

 

[Doc McPeak]

Someone mentioned krumholtz being a German word. It is actually of Romanian origin, and more specifically, Transylvanian. These interesting dwarf trees were bred by an iconoclastic Count of the order of the Dracul, who filled them with a lust for flesh and an insatiable thirst for human blood. Though relatively harmless and benign during the day, aside from the copious amounts of blood loss they hold credit to, at night they have been known to devour whole packs of moonlight bushwhackers.

 

[Dr. Dasypodidae]

Another recent observation about krummholz is that the individual trees and tree islands are becoming increasingly viable and treeline is moving upwards in the alpine and farther north in the boreal ecotones, most probably driven by Global Warming. Within a few decades we may well lose our tundra areas in northern New England and New York state.