Why Do Joshua Trees Grow

Joshua trees are relatively fast growers for desert plants. Seedlings will grow at an average rate of 7.6 cm (3 inches) per year in their first ten years. Seedlings will then slow to 3.8 cm (1.5 inches) per year. Many desert plants need to grow to a height of about 1 meter to escape high ground temperatures and shading of adjacent plants, which will negatively affect their growth rate. Joshua trees can exceed 3 meters, which allows them to escape these pressures. DeFalco et al. believes this investment in height is worth the effort because it can result in increased resistance to fire mortality [3]. The tallest trees can reach about 15 meters (49 feet) in height. An unusual characteristic of Joshua trees is their lack of annual growth rings. This lack of rings is due to the composition of the trunk, which is made of thousands of small fibers. A lack of annual growth rings makes it difficult to determine the age of Joshua trees. Along with a top-heavy branch system, Joshua trees have an extensive root system, which aids in their dispersal. Most new trees grow from seedlings, but in some populations new …show more content…
Joshua trees usually do not branch until after they bloom and they typically do not bloom every year. A commonality of desert plants is that their flowering is dependent on the amount and timing of rainfall in a season. Once flowering occurs, the yucca moth pollinates neighboring Joshua trees while laying its eggs inside the flower. Without this moth the Joshua tree could not reproduce, nor could the moth, whose larvae needs the seeds as nutrient. This connection between the Joshua tree and yucca moth is a clear example of a symbiotic relationship. This crucial exchange could be in jeopardy with the impending climate change. Climate change will affect the timing of the seasons, which could disrupt the mating pattern of the moth. This issue is discussed in the conservation challenges section of this