Simone Santos Lira Silva

Grasses are widely used in extensive green roofs due to their ecological performance, yet fire-risk assessments for these systems remain scarce. Understanding species specific flammability is essential because vegetation drying, especially under low irrigation, may increase ignition potential in urban infrastructures. This study evaluated the flammability of native and commercial grass genotypes to identify safer options for green roof applications. The experiment was conducted simulating the conditions of an extensive green roof. Genotypes of Paspalum notatum (BRA006513, BRA019178, BRA023558, and the cultivars Aruaí, Tiriba, and Tuim), Axonopus parodii (cv. Curica), and Zoysia japonica as a reference species were cultivated from seedlings for 365 days. Morphological characteristics, biomass moisture, fire behavior parameters, surface temperatures, and grass plate weight were measured under controlled burning. Species differed significantly in fire behavior. Z. japonica exhibited the highest flame height (65 cm), rate of spread (0.03 m s-1), and fire intensity (24.56 kcal m-1 s-1), whereas BRA023558 showed the lowest susceptibility to fire. Moisture content varied among genotypes but was not correlated with fire parameters. Grass species vary widely in fire behavior parameters. These results support evidence-based plant selection for safer and more resilient urban green infrastructure. Thus, the BRA023558 genotype showed lower susceptibility to fire under burning conditions.

The selection of a genotype for lawn use must consider the plant survival rate and its soil covering ability, which is directly influenced by the growth of stolons and rhizomes. This study aimed to evaluate the growth and development of Paspalum accession plugs for turfgrass establishment. Plugs of six prostrate growth accessions of Paspalum lepton (PL 01), P. notatum (from PN 01 to PN 06) and Zoysia japonica (ZJ 01), which was used as the control treatment, were planted adding up to 7 treatments. At 63 days after planting, the survival rate, the number of shoots, the expansion capacity, plant height and soil coverage rate were evaluated. Moreover, at 72 days after planting, fresh and dry leaf, root, rhizome and/or stolon biomass, as well as root length were evaluated. Plugs of PL 01 presented the highest values regarding the number of shoots, the expansion capacity, soil coverage and the development of the root system with the largest biomass production. PL 01 and PN 05 along with ZJ 01 presented a high soil coverage rate and all the P. notatum (PN) accessions together with ZJ 01 maintained a lower plant height, but with a length root system higher than the control treatment ZJ 01. The P. lepton (PL 01) and P. notatum (PN 05) accessions can be recommended for turfgrass establishment using plug propagation methods.