Wood harvesting and storage (WHS) is a hybrid Nature-Engineering combination method to combat climate change by harvesting wood sustainably and storing it semi-permanently for carbon sequestration. To date, the technology has only been purposefully tested in small-scale demonstration projects. This study aims to develop a concrete way to carry out WHS at large-scale. We describe a method of constructing a wood storage facility, named Wood Vault, that can bury woody biomass on a mega-tonne scale in specially engineered enclosures to ensure anaerobic environments, thus preventing wood decay. The buried wood enters a quasi-geological reservoir that is expected to stay intact semi-permanently. Storing wood in many environments is possible, leading to seven versions of Wood Vault: (1) Burial Mound (Tumulus or Barrow), (2) Underground (Pit, Quarry, or Mine), (3) Super Vault, (4) Shelter, (5) AquaOpen or AquaVault with wood submerged under water, (6) DesertOpen or DesertVault in dry regions, (7) FreezeVault in cold regions such as Antarctica. Smaller sizes are also possible, named Baby Vault. A prototype Wood Vault Unit (WVU) occupies 1 hectare (ha, 100 m by 100 m) of surface land, 20 m tall, stores up to 100,000 m3 of wood, sequestering 0.1 MtCO2. A 1 MtCO2 y−1 sequestration rate can be achieved by collecting currently unused wood residuals (WR) on an area of 25,000 km2, the size of 10 typical counties in the eastern US, corresponding to an average transportation distance of less than 100 km. After 30 years of operation, such a Wood Vault facility would have sequestered 30 MtCO2, stored in 300 WVUs, occupying a land surface of 300 ha. The cost is estimated at $10–50/tCO2 with a mid-point price of $30/tCO2. To sequester 1 GtCO2 y−1, wood can be sourced from currently unexploited wood residuals on an area of 9 Mkm2 forested land (9 million square kilometers, size of the US), corresponding to a low areal harvesting intensity of 1.1 tCO2 ha−1 y−1. Alternatively, giga-tonne scale carbon removal can be achieved by harvesting wood at a medium harvesting intensity of 4 tCO2 ha−1 y−1 on 3 Mkm2 of forest (equivalent to increasing current world wood harvest rate by 25%), or harvest on 0.8 Mkm2 forest restored from past Amazon deforestation at high harvest intensity, or many combinations of these and other possibilities. It takes 1000 facilities as discussed above to store 1 GtCO2 y−1, compared to more than 6000 landfills currently in operation in the US. After full closure of a Wood Vault, the land can be utilized for recreation, agriculture, solar farm, or agrivoltaics. A more distributed small operator model (Baby Vault) has somewhat different operation and economic constraints. A 10 giga-tonne sequestration rate siphons off only 5% of total terrestrial net primary production, thus possible with WHS, but extreme caution needs to be taken to ensure sustainable wood sourcing. Our technical and economic analysis shows that Wood Vault can be a powerful tool to sequester carbon reliably, using a variety of wood sources. Most pieces of the technology already exist, but they need to be put together efficiently in practice. Some uncertainties need to be addressed, including how durability of buried wood depends on detailed storage methods and burial environment, but the science and technology are known well enough to believe the practicality of the method. The high durability, verifiability and low-cost makes it already an attractive option in the current global carbon market. Woody biomass stored in Wood Vaults is not only a carbon sink to combat current climate crisis, but also a valuable resource for the future that can be used as biomass/bioenergy and carbon supply. The quantity of this wood utilization can be controlled carefully to maintain a desired amount of CO2 in the atmosphere to keep the Earth’s climate from diving into the next ice age, acting as a climate thermostat. The CO2 drawdown time is on the order of 100 years while the ramp-up time is a decade. A sense of urgency is warranted because the CO2 removal rate is limited by biosphere productivity, thus delayed action means a loss of opportunity. In conclusion, WHS provides a tool for managing our Earth system, which will likely remain forever in the Anthropocene.

中文翻译：

---

Wood Vault：用树木去除大气中的二氧化碳，储存木材用于现在的碳封存以及未来的生物质、生物能源和碳储备

木材采伐和储存 (WHS) 是一种混合自然与工程相结合的方法，通过可持续地采伐木材并将其半永久性储存以进行碳封存，从而应对气候变化。迄今为止，该技术仅在小规模示范项目中进行了有目的地测试。本研究旨在开发一种大规模开展 WHS 的具体方法。我们描述了一种建造名为 Wood Vault 的木材储存设施的方法，该设施可以在特殊设计的外壳中以兆吨级的规模掩埋木质生物质，以确保厌氧环境，从而防止木材腐烂。埋藏的木材进入一个准地质储层，预计将保持半永久性完好。在许多环境中存储木材是可能的，从而产生了七个版本的 Wood Vault：(1) 古坟（古坟或手推车），(2) 地下（坑、采石场、或矿山），（3）超级避难所，（4）避难所，（5）AquaOpen或AquaVault，木材淹没在水下，（6）干旱地区的DesertOpen或DesertVault，（7）南极洲等寒冷地区的FreezeVault。更小的尺寸也是可能的，命名为 Baby Vault。原型 Wood Vault Unit (WVU) 占地 1 公顷（公顷，100 m x 100 m），高 20 m，可储存多达 100,000 m3 的木材，隔离 0.1 MtCO2。1 MtCO2 y-1 的封存率可以通过在 25,000 平方公里（相当于美国东部 10 个典型县的面积）上收集当前未使用的木材残渣 (WR) 来实现，对应的平均运输距离不到 100 公里。经过 30 年的运营，这样的 Wood Vault 设施将隔离 30 MtCO2，储存在 300 个 WVU 中，占地 300 公顷。成本估计为 10-50 美元/吨二氧化碳，中间价为 30 美元/吨二氧化碳。为了封存 1 GtCO2 y−1，木材可以从 9 Mkm2 林地（900 万平方公里，美国的面积）上目前未开发的木材残渣中获取，对应于 1.1 tCO2 ha−1 的低面积采伐强度y-1。或者，可以通过在 3 Mkm2 的森林上以 4 tCO2 ha-1 y-1 的中等采伐强度采伐木材（相当于将当前世界木材采伐率提高 25%），或在0.8 Mkm2 森林从过去的亚马逊森林砍伐中以高采伐强度恢复，或这些和其他可能性的许多组合。如上所述，储存 1 GtCO2 y−1 需要 1000 个设施，而美国目前有 6000 多个垃圾填埋场。在完全关闭 Wood Vault 后，该土地可用于娱乐、农业、太阳能农场或农业发电。更分散的小型运营商模型（Baby Vault）具有一些不同的运营和经济约束。10 吉吨的封存率仅吸走陆地净初级生产总量的 5%，因此可以通过 WHS 实现，但需要格外小心以确保可持续的木材采购。我们的技术和经济分析表明，Wood Vault 可以成为可靠地隔离碳的强大工具，它使用各种木材来源。大多数技术已经存在，但需要在实践中有效地组合在一起。需要解决一些不确定性，包括埋藏木材的耐久性如何取决于详细的储存方法和埋藏环境，但科学技术广为人知，足以相信该方法的实用性。高耐用性、可验证性和低成本使其在当前全球碳市场中已经成为一个有吸引力的选择。储存在 Wood Vaults 中的木质生物质不仅是应对当前气候危机的碳汇，也是未来可用作生物质/生物能源和碳供应的宝贵资源。可以仔细控制这种木材利用的数量，以保持大气中所需的二氧化碳量，以防止地球气候进入下一个冰河时代，起到气候恒温器的作用。CO2 下降时间约为 100 年，而加速时间为 10 年。紧迫感是必要的，因为二氧化碳去除率受到生物圈生产力的限制，因此，延迟行动意味着失去机会。总之，WHS 为管理我们的地球系统提供了一个工具，该系统可能会永远存在于人类世。