Burstiness of seed production in longleaf pine and Chinese torreya
Different trees may have different seed production behaviors. Understanding the spatial and temporal patterns in seed production is important for sustainable forest management. A common feature in many complex systems is burstiness in their activity patterns. Burstiness is defined here as intermittent seed production. We studied burstiness in the seed (cone) production of longleaf pine (Pinus palustris) and Chinese Torreya (Torreya grandis) for the first time. Results indicated that burstiness characterized the seed production for both tree species. Burstiness ranged between low negative and low positive values and varied by species and locations. Generally, there existed scaling relationships between seed production and average inter-event years for both species, but the scaling exponents were different at locations. The average inter-event time was long for episodes of high seed production. These results suggest that complex seed production systems may be governed by some generic principles. Understanding burstiness in tree seed production may provide new knowledge about tree growth dynamics and their reproduction behaviors. This would be useful in sustainable forest management for estimating when the next high seed production episode is likely to occur and identifying sites with a short interevent time for high seed production.