Remnant Trees in Enrichment Planted Gaps in Quintana Roo, Mexico: Reasons for Retention and Effects on Seedlings

Abstract

Natural forest management in the tropics is often impeded by scarcity of advanced regeneration of commercial species. To supplement natural regeneration in a forest managed by a community in the Selva Maya of Mexico, nursery-grown Swietenia macrophylla seedlings were planted in multiple-tree felling gaps, known as bosquetes. Remnant trees are often left standing in gaps for cultural and economic reasons or due to their official protected status. We focus on these purposefully retained trees and their impacts on planted seedlings. Sampled bosquetes were 400-1800 m 2 , of which remnant trees covered a mean of 29%. Seedling height growth rates over the first 18 months after out-planting more than doubled with increased canopy openness from 0.09 m year −1 under medium cover to 0.22 m year −1 in full sun. Liana infestations and shoot tip damage were most frequent on seedlings in the open, but, contrary to our expectations, height growth rates were 0.14 m year −1 faster for liana-infested seedlings than non-infested and did not differ between damaged and undamaged seedlings. Apparently the more rapid height growth of well-illuminated seedlings more than compensated for the effects of lianas or shoot tip damage. Despite the abundance of remnant trees and their negative effects on seedling growth, enrichment planting in bosquetes has potential for community-based natural forest management in the tropics in supplementing natural regeneration of commercial species. One obvious recommendation is to leave fewer remnant trees, especially those of commercial species that are non-merchantable due to stem defects and trees retained for no apparent reason, which together constituted half of the remnant crown cover in the sampled bosquetes. Finally, given the rapid growth of lianas and understory palms in large canopy gaps, at least the most vigorous of the planted seedlings should be tended for at least two years.

Traditional Ecological Knowledge in Community Forest Management: Evolution and Limitations in Mexican Forest Law, Policy and Practice

“…Conventional silvicultural practices generally focus on improving forest stand growth, product quality and economic efficiency; sometimes contradicting local rationalities where felling trees is only justified in case of current necessity and direct use [139,140]. As documented elsewhere, not all communities involved in CFM strive to maximize profit from forest management; other important factors shaping decisions being cultural values of forests (recreational and spiritual activities), a concern for biodiversity conservation [109], production of public goods and services, supplying products for household use to community members, and very importantly to maximize employment [141,142]. These contrasting rationalities have been a source of tensions, particularly at the inception of forestry programs.…”

“…While the regional economic importance of this species as a source of chicle, an NTFP, has steeply declined in the last five decades, and various communities now harvest M. zapota timber, in some Mayan communities these trees still tend to be protected as a legacy of the chicle tapping culture, and also due to its role in producing fruits that feed wild game important for local livelihoods [103]. Thus, the success of CFM can be explained by the permanence of TEK and related practices that complement or address failures of the conventional management plans: for instance, in Noh Bec, a community long considered to be a poster child of tropical CFM, local logging operators go slightly off-script from what is considered in the management plan, and retain individuals of lesser-known tree species that they recognize to be marketable in the emergent market for tourist construction materials [141].…”

“…In Mexico, out of a sample of 2616 forest communities, 35% lead logging operations, while in 27% of them logging operations are led by external contractors and timber buyers, and the remaining 38% are potential forest producers [191]. Local crews take decisions regarding logging based on their own criteria and knowledge [141], which may differ from what is stated in management plans or the criteria of external logging contractors that are more focused on immediate profit and less on forest sustainability [119,192]. In some contexts, local crews with specialized TEK but with limited technical training, are hired to harvest and process forest products including charcoal, NTFPs, and logging from trees outside-forests [116].…”

Carbon emissions from selective logging in the southern Yucatan Peninsula, Mexico

“…Both ejidos apply a polycyclic silvicultural system with a 75-year rotation and a 25-year cutting cycle based on the growth and yield of mahogany (Swietenia macrophylla King), the guiding timber species for silviculture in the region (Ellis et al, 2015;Navarro-Martínez et al, 2017). Timber harvesting must be done according to an authorized Forest Management Plan, for a period of 10 years to 20 years depending on the size of the management area and number of annual cutting areas (ACA).…”

An experiential, adaptive, inexpensive, and opportunistic approach to research capacity building in the tropics

“…The manuscript that represented the work of the entire group in Mexico was rejected by Forest Ecology and Management in part because of a weak statistical approach, but with that problem rectified, it was published in Forests (Navarro‐Martínez et al . ).…”