An vital function of seed dormancy is delayed germination, which allows dispersal and prevents simultaneous germination of all seeds. The staggering of germination safeguards some seeds and seedlings from suffering damage or loss of life from brief intervals of bad weather or from transient herbivores; it additionally allows some seeds to germinate when competition from different plants for mild and water might be less intense. Another form of delayed seed germination is seed quiescence, which is different from true seed dormancy and happens when a seed fails to germinate as a result of the external environmental conditions are too dry or warm or cold for germination. Many species of plants have seeds that delay germination for many months or years, and a few seeds can remain within the soil seed financial institution for more than 50 years before germination. Seed dormancy is particularly adaptive in hearth-prone ecosystems. Some seeds have a very lengthy viability period, and the oldest documented germinating seed was practically 2000 years outdated based on radiocarbon dating.