The Intricacies of a forest ecosystem or Nurse Logs and the Plants that Love Them

The purpose of this investigation was to find patterns (if any) that exist when comparing the dominant plant organisms atop nurse logs in two 12’x13’ quadrats along the Marsh Loop and Suspension Bridge trails at IslandWood. The intent of this investigation was to elucidate why certain plants grow on decaying wood. Two locations were chosen in the temperate second-growth forest at IslandWood. Two quadrats were designated for repeated observations. An investigator observed, recorded and researched the organisms found atop the nurse logs within each quadrat. Observations, data recording and research on plant communities within and around each quadrat also occurred. The investigator inferred throughout the process, while immersing herself in the landscape. Comparisons were made, two patterns emerged and many inferences were debunked by subsequent research on the following: bark fragmentation, decay classification, bryophyte/nurse log relationships, tree seedling growth, and plant regeneration. Two major learnings are a result of this investigation. 1) Fallen log decomposition requires quite a few years before tree seedling establishment can occur. 2) Succession happens on nurse logs as well, which is largely determined by decay class and chance. Introduction Myriad field guides, books and studies discuss the importance of decaying wood in forest ecosystems and some even point out distinct relationships between nurse logs and particular plant species. Numerous studies indicate that nurse logs are nutrient-rich substrates for a variety of plant species (Kennedy and Quinn, 2000). It is established that certain plants thrive on nurse logs. For example in the field guide, Plants of the Pacific Northwest Coast, co-authors and editors, Jim Pojar and Andy MacKinnon included the following in their description of the liverwort, Lepidozia Reptans (Little hands liverwort). It reads, “The stage of decay of the rotting wood is important to Lepidozia. “Kickable” stumps—those with a pleasant soft sound when kicked—almost always have Lepidozia and Tetraphis; stumps in early stages of decay have harder substrates and often have species of...”(441). Readers are left to wonder why Lepodozia react differently than other bryophytes to harder decayed wood. The same occurs here in Xuan Guo’s paper, “Natural Regeneration on Course Woody Debris,” he writes, “Although logs provide advantageous habitats for some species, they are inferior seedbeds for other species; for example maple