Abstract:

The purpose is to quantify the damage caused by Monochamus saltuarius to the forest carbon sink of the Suiyang forest area in Heilongjiang Province, which serves as a key barrier against the northward invasion of pine wilt disease (Bursaphelenchus xylophilus), assess its economic impact, and propose prevention and control strategies to maintain regional ecological security and carbon sink function. Based on standard plot surveys, ecosystem carbon stocks were estimated using a dual-track carbon assessment approach (the conversion factor continuous function method combined with the growing stock expansion method). Pest-induced impacts were assessed by analogy with the carbon loss rate of Monochamus alternatus (34.46%), and carbon sink values were monetized at USD 150 per ton. The results indicated that spruce and fir together accounted for 46.26% of the regional total carbon stock, highlighting their critical role due to high carbon density. The potential pest-affected area reached 18.77%, with the infestation rate of damaged trees in Sanchakou Forest Farm as high as 42.00%. Pest outbreaks resulted in a forest carbon loss of 120400 t, corresponding to an economic loss of at least USD 18.06 million. Resource-rich forest farms such as Xilinhe and Qingshan were identified as both core carbon storage areas and hotspots for pest spread. The study demonstrates that Monochamus saltuarius poses a severe threat to carbon sink functions by damaging high carbon-sequestration tree species. An urgent need exists to establish a zoned management framework: deploying UAV-based monitoring networks and releasing the natural enemy Dastarcus helophoroides in core zones; applying pheromone trapping and replacing pure spruce stands with resistant tree species in transition zones. In parallel, the exploration of “carbon sink insurance” is recommended to hedge risks, thereby maintaining the strategic role of the region as both a disease barrier and a carbon sink reserve.

Key words: Monochamus saltuarius, forest carbon sinks, economic value of carbon sequestration, northward expansion of pine wilt disease, carbon sink insurance