why don't Herbs and shrubs grow upright in the tundra
http://ths.sps.lane.edu/biomes/tundra3/tundra3.html
See the Vegatation section.
In the tundra biome, herbs and shrubs typically don't grow upright due to several factors. The main reasons are the harsh environmental conditions and the characteristics of the plants themselves.
The tundra is a cold and windy biome with a short growing season and poor soil quality. The ground is often frozen, limiting the availability of nutrients and water. These conditions make it challenging for plants to thrive and grow tall.
Firstly, the cold temperatures in the tundra restrict plant growth. Most plants have an optimal temperature range for growth, and the low temperatures in the tundra can hinder their development. The cold temperatures can slow down or even halt the growth of herbs and shrubs, preventing them from reaching their full height.
Secondly, the strong winds in the tundra can be a significant factor in stunting plant growth. The continuous exposure to strong winds can cause desiccation and breakage of above-ground plant parts. To adapt to these conditions, tundra plants often grow close to the ground, forming a low, mat-like structure to reduce wind resistance and prevent damage.
Lastly, the lack of nutrients and water in the tundra soil also affects the growth of herbs and shrubs. The frozen ground prevents plants from accessing the nutrients and water needed for upright growth. Tundra plants have adapted by developing shallow root systems to make use of the limited nutrients available near the surface. This shallow rooting system helps them survive, but it limits their ability to grow tall and upright.
Therefore, the combination of cold temperatures, strong winds, and poor soil quality in the tundra biome contributes to the stunted growth and low stature of herbs and shrubs. If you would like to explore more information regarding this topic, you can visit the link you provided (http://ths.sps.lane.edu/biomes/tundra3/tundra3.html) and refer to the "Vegetation" section for a more detailed explanation.