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Balancing moose (Alces alces) populations with forest production objectives remains a major challenge in Swedish boreal forestry. Browsing damage is commonly assessed using empirical indices, while the underlying availability of browsable shoot biomass is rarely quantified mechanistically. We developed a mechanistic, data-driven model of browse availability in young Scots pine (Pinus sylvestris) by linking shoot-level allometry, crown architecture, and tree height development. Empirical data were collected from nine unbrowsed trees, for which current-year shoots were measured by branch whorl, including shoot length, shoot number, and wet/dry biomass ratio. Shoot scaling with crown position was analysed to quantify crown allometry and distribution. Crown architecture was coupled with a height–age growth model to simulate vertical crown development and estimate shoot biomass accessible to moose browsing within a defined browsing height for moose. Simulations were conducted across site productivity classes and scaled to the stand level. Shoot biomass, length and diameter increased with tree height and declined exponentially with distance from the apex with 50%, 33% and 13% per whorl, respectively. At the crown level, both total shoot length and biomass followed unimodal distributions, peaking near the vertical midpoint of the crown. Simulations showed that browse availability increased rapidly with tree growth, peaked at tree heights around 3.5 m (15–25 years depending on site productivity), and subsequently declined. Peak shoot biomass ranged from 330 to 450 g per tree, with high-productivity sites yielding up to 35% more biomass. When scaled to stands ≤2.5 m in height at 2,000 stems ha⁻¹, simulated browse availability was 100–200 kg ha⁻¹. These results show that crown architecture in young Scots pine follows consistent scaling rules that can be expressed as functions of tree height and crown position. The model provides a mechanistic connection between tree growth and herbivore-accessible forage and implications for management is discussed.