Early Survival and Growth of Introduced Western Coast and Mexican Pine Species in East Texas

Changing climates across the United States has prompted concern as droughts are becoming more severe and frequent in the last 100 years. The southeastern portion of the United States produces almost a quarter of the world’s timber. With this region being vital to timber industry, a potential for a shift in growing conditions could be detrimental to the current species in the southeastern United States. In anticipation of the shifting climate in the East Texas region non-native pine species nay need to be considered as a possibility to be used by the timber industry in the future. Containerized seedlings of two United States western pine species (ponderosa, Pinus ponderosa and Jeffrey pine P. jeffreyi) were planted in 2021 and three Mexican pine species (Caribbean, P. caribaea, Durango, P. durangensis, and Mexican weeping P. patula) planted in 2023 were evaluated for survival and growth compared to native loblolly (P. taeda) and shortleaf (P. enchinata) pines planted at the same time. Seedlings were evaluated at four sites in Houston and Cherokee Counties, seedling growth and survival was recorded in December-January of 2022, December-January of 2023, and January of 2024. Survival was also recorded in June-July of 2022, and July of 2023. After two years, of the seedlings planted in 2021, loblolly pine had the greatest survival. Mexican pine seedlings planted in 2023 had low survival rates, with shortleaf having the greatest survival. Loblolly pine heights were greater ponderosa or Jeffery pines after two years; diameters were greater for ponderosa pine in the first year, but not in the second year. As expected, the native loblolly pine and shortleaf pine had the greatest diameter and height growth. Of the other species, ponderosa pine had the greater survival and growth of the 2021 species and the Mexican Weeping pine of the 2023 species. Contributing factors could have influenced the survival and growth of the seedlings. The occurrence of drought and extreme weather conditions during the summers of 2022 and 2023 and below average growing season precipitation that limited available soil moisture. Influences from understory vegetation and the ecological differences of the forest stand structure could have lessen chances for species establishment compared to their native ecosystem. Differences such as soils at the study sites compared to native range soils and the presence of competing vegetation not observed in other species ecosystem and seedling uprooted from feral hogs. Management decisions that are not practiced with the non-native species such as, time of planting compared to recommended timing in native regions, and/ or poor planting technique while planting could have impacted seedling success. Future research should be conducted to further explore potential species for the anticipated climates with more tests to provide further explanation of species survival and growth.