Supporting Growth and Transpiration of Newly Planted Street Trees With Passive Irrigation Systems

Abstract

Solutions that use stormwater runoff to rapidly establish tree canopy cover in cities have received significant attention. Passive irrigation systems that direct stormwater to trees have the potential to increase growth and transpiration and may limit drought stress. However, little data from the field demonstrates this, and we lack robust and reliable designs which achieve it. Here, we quantified growth and transpiration for trees: (a) in infiltration pits receiving stormwater, with a raised underdrain and internal water storage (drained), (b) next to infiltration pits receiving stormwater but without an underdrain and internal water storage (adjacent), and (c) planted in standard pits, not receiving stormwater (control). Trees in drained pits grew twice as fast as control trees in the first 2 years, but fast initial growth rates were not sustained in years three and four. Trees outgrowing the small infiltration pits, rather than a lack of water, was most likely responsible for growth rates slowing down. Despite this, rapid initial growth for trees in drained pits meant trees were larger by year three and transpired more than twice as much (5.1 L d−1) as trees adjacent to pits (2.4 L d−1) or control trees (2.3 L d−1). No trees showed drought stress during the study. However, some trees planted adjacent to infiltration pits showed waterlogging stress, suggesting caution installing infiltration pits adjacent to establishing trees in fine‐textured soils. Overall, our results suggest passive irrigation systems can substantially increase initial tree growth, thereby facilitating greater cooling and runoff reduction through increased transpiration.

Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California

“…Expanding on this current study to explore a broader range of tree species could be used to develop combined irrigation and species selection strategies. Similarly future work could expand on the range of climate scenarios considered, and importantly consider more complex irrigation and water management strategies such as mulching to reduce water loss (Wang et al, 2021), or storm water redirection to fulfill irrigation requirements (Thom et al, 2022).…”

Effect of Transpiration on the Monocot Ornamental Plants Leave Anatomy

“…Furthermore, these plants produce oxygen-rich air and absorb CO2, thereby improving air quality (Widyastuti 2018). These processes are greatly influenced by various physiological activities, such as transpiration (Williams et al 2021;Thom et al 2022), which is essential for growth, as it helps to regulate leaf and environmental temperatures (Salisbury and Ross 1995;Sundberg 1985;Gao et al 2020). However, excessive transpiration can lead to issues such as wilting, drought, and death (Beckman, 1964), which diminishes the beauty of ornamental plants (Toscano et al 2019) and change leaf anatomy (Boughalleb et al 2014).…”