Estimating Litter Production Amount and Quality for Eldar Pine and Umbraculifera Elm Trees in the Historic City of Yazd

Abstract

This study aimed to estimate the amount and quality of litter produced by pine and elm trees in the green space of the historic city of Yazd. Litterbags were used to collect the leaves for a year while the amount of nitrogen, phosphorus, calcium, sulfur, carbon, magnesium, and potassium levels was measured monthly for both species. The annual mean weight of all components of litter was found to be 4056.56 g for pine and 4106.67 g for elm trees. The results showed that the greatest fall of pine needles was recorded in September, while the highest fall of elm leaves was measured in November. The specific leaf area of elm and pine was calculated to be 169.38 and 29.96 cm²/g, respectively. The leaf area index for pine and elm was 0.91 and 7.99, respectively. There was no statistically significant difference between pine and elm trees in the leaf amount and total litter. However, the crown area of pine and elm trees had a direct effect on the amount of total litter produced (R² = 0.72 and 0.60 respectively). There was a significant difference between the two species in organic matter percentage, while there was no significant difference in the carbon, calcium, and magnesium content. The specific leaf area of elm was higher than pine, making it better in this index. According to the amount of annual litter production of two species calculated in this research, it can be said that in the city of Yazd, pine and elm trees produce at least 158.9 and 804.5 tons of litter per year respectively. Since the minimum cost of litter collection per hectare of tree plantations in the city is $150, collecting pine and elm litter will cost the municipality $14,700 and $73,500, respectively. Our study showed that contrary to popular belief, pine needles play an important role in total leaf litter produced in arid regions like Yazd. Also, the process of collecting dead leaves continues throughout the year, especially in summer in arid areas.