The slow rate of decomposition of fallen logs in nature is due to their low moisture content.

Explanation:
The decomposition of fallen logs in nature is a natural process that involves the breakdown of organic matter by microorganisms such as bacteria and fungi. These microorganisms require certain conditions to thrive and effectively decompose the logs. One of the essential factors for decomposition is moisture content.

1. Importance of Moisture:
Moisture is crucial for the growth and activity of decomposer microorganisms. It provides the necessary medium for them to carry out metabolic processes and enzymatic reactions that break down the organic matter. Adequate moisture facilitates the movement of nutrients and helps create an environment suitable for decomposition.

2. Effect of Low Moisture Content:
When fallen logs have low moisture content, it hampers the decomposition process. The lack of moisture restricts the growth and activity of decomposer microorganisms. Without sufficient water, these microorganisms are unable to carry out their enzymatic reactions effectively, resulting in slower decomposition.

3. Consequences of Slow Decomposition:
The slow rate of decomposition has several implications for the ecosystem:

- Nutrient Cycling: Decomposition is a crucial process in nutrient cycling, as it releases nutrients stored in organic matter back into the soil. Slow decomposition of fallen logs means that these nutrients are not readily available for other organisms, affecting the overall nutrient balance in the ecosystem.

- Habitat Creation: Fallen logs provide habitats for various organisms, including insects, fungi, and small mammals. Slow decomposition means that these habitats persist for longer periods, supporting a diverse range of species.

- Carbon Sequestration: Fallen logs contain carbon in the form of cellulose and lignin. Slow decomposition leads to the long-term storage of carbon in the logs, contributing to carbon sequestration and potentially mitigating climate change.

In conclusion, the slow rate of decomposition of fallen logs in nature is primarily due to their low moisture content. This lack of moisture limits the growth and activity of decomposer microorganisms, hindering their ability to break down the organic matter efficiently.