Castle Howard Arboretum — Data Exploration

1 Overview

The dataset contains 9,519 accessions spanning 102 families, 343 genera, 1,834 accepted names, and 3,327 unique raw names, planted across 149 areas. Planting years range from 1946 to 2020.

Figure 1: Collection summary — accessions, families, genera, accepted names, and raw names

2 Top Species (Accepted Names)

Figure 2: Top 20 accepted species — determined to species level or lower

3 Genus Composition

Top genera

Figure 3: Top 20 genera — bars partitioned by determination level

Genus diversity

Table 1

4 Planting Year

30.4% of accessions have no planting year recorded.

Figure 4: Accessions planted per decade

5 Collectors

Only 20.7% of accessions have a named collector.

Top collectors

Figure 5: Top 20 collectors by accession count

Collector genus preferences

Table 2

6 Sources

Table 3

7 Overlap with Kew Living Collection

Matching Castle Howard accessions to Kew + Wakehurst (Living and Seed/MSB collections combined) using:

• Strong (name + code): accepted name matches AND at least one of Collector Code / Collector Name / Source matches a Kew OtherCollectionSeries / Donor / DonorCode
• Accepted name only: accepted name present at Kew but no collector/donor signal
• CHA only: accepted name at Castle Howard not found at Kew/Wakehurst

Table 4: Match level summary

match_level	Accessions	%
Strong (name + code)	2852	30.0
Accepted name only	5777	60.7
CHA only	862	9.1
Unmatched taxon	28	0.3

Accessions by source

Figure 6: Accessions per year by source — Kew and Wakehurst contributions highlighted, with unknown-source accessions separated

Spike year sources

Table 5

Overlap by genus

Figure 7: Overlap with Kew/Wakehurst by match strength — top 15 genera

CHA-only names

Table 6

8 Taxa Not Backed Up at Kew or Wakehurst

Accepted names present at Castle Howard Arboretum but absent from both Kew, Wakehurst and/or the MSB.

Table 7

349 accepted species at Castle Howard Arboretum are not held at Kew, Wakehurst or the MSB.

9 Summary

• The collection holds 9,519 accessions across 1,834 accepted names.
• Planting activity peaked in the 1980s and 1990s, with a decline in more recent decades.
• 349 accepted species at Castle Howard have no backup at Kew or Wakehurst.