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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ISPRS-Archives</journal-id>
<journal-title-group>
<journal-title>The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences</journal-title>
<abbrev-journal-title abbrev-type="publisher">ISPRS-Archives</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">2194-9034</issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/isprs-archives-XLIX-B1-2026-457-2026</article-id>
<title-group>
<article-title>Linking TreeQSM with SAR and ALS to Detect Internal Canopy Allocation Shifts Across Scales</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sorokina</surname>
<given-names>Hanna</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Campos</surname>
<given-names>Mariana</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Korpelainen</surname>
<given-names>Taiga</given-names>
<ext-link>https://orcid.org/0009-0004-5702-7922</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Echriti</surname>
<given-names>Rami</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Puttonen</surname>
<given-names>Eetu</given-names>
<ext-link>https://orcid.org/0000-0003-0985-4443</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hyyppä</surname>
<given-names>Juha</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Wang</surname>
<given-names>Yunsheng</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Finnish Geospatial Research Institute (FGI), National Land Survey of Finland, Vuorimiehentie 5, 02150 Espoo, Finland</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Department of Geosciences and Geography, University of Helsinki, Fabianinkatu 33, 00014 University of Helsinki, Finland</addr-line>
</aff>
<pub-date pub-type="epub">
<day>22</day>
<month>07</month>
<year>2026</year>
</pub-date>
<volume>XLIX-B1-2026</volume>
<fpage>457</fpage>
<lpage>464</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Hanna Sorokina et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://isprs-archives.copernicus.org/articles/XLIX-B1-2026/457/2026/isprs-archives-XLIX-B1-2026-457-2026.html">This article is available from https://isprs-archives.copernicus.org/articles/XLIX-B1-2026/457/2026/isprs-archives-XLIX-B1-2026-457-2026.html</self-uri>
<self-uri xlink:href="https://isprs-archives.copernicus.org/articles/XLIX-B1-2026/457/2026/isprs-archives-XLIX-B1-2026-457-2026.pdf">The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/XLIX-B1-2026/457/2026/isprs-archives-XLIX-B1-2026-457-2026.pdf</self-uri>
<abstract>
<p>Linking remotely sensed forest backscatter with fine-scale tree crown structural dynamics provides insights into tree growth strategies under varying conditions. In this study, we investigate whether branch-scale tree growth allocation dynamics, derived from multi-temporal TreeQSM models, are reflected in SAR and ALS observations. We analyzed branch organization dynamics of silver birch (&lt;em&gt;Betula pendula&lt;/em&gt;) using terrestrial laser scanning data from 2021, 2023 and 2025 at a boreal forest site in southern Finland. Branch allocation metrics, including volume-weighted mean diameter (VWMD), small branch fraction (SBF), distal volume fraction, relative branch height, and top canopy volume, were quantified to capture shifts between structural reinforcement and exploratory growth. These metrics were compared with Sentinel-1 SAR features (&amp;alpha;, entropy, C&lt;sub&gt;11&lt;/sub&gt;, C&lt;sub&gt;22&lt;/sub&gt;) and ALS-derived canopy metrics (plant area index, vertical complexity index) alongside local structural variables. Results show a consistent trade-off between coarse and fine branching, with strong negative correlations between &amp;Delta;VWMD and &amp;Delta;SBF across both periods (&amp;rho; = &amp;ndash;0.92). SAR-derived &amp;alpha; exhibits strong associations with these allocation shifts during 2021&amp;ndash;2023 (&amp;rho; = &amp;ndash;0.81 with &amp;Delta;VWMD; &amp;rho; = 0.75 with &amp;Delta;SBF), indicating sensitivity to internal redistribution of branch material. ALS metrics from 2021 reflect initial canopy structure and are associated with subsequent allocation shifts. Despite the small magnitude of observed changes, consistent monotonic relationships across datasets suggest that subtle within-crown branch allocation is detectable from satellite and aerial observations, reflecting the surrounding canopy context. However, weakened correlations in 2023&amp;ndash;2025 highlight the influence of external factors on SAR signals.</p>
</abstract>
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