木材基本密度是决定松类人工林木材质量的重要性状。Pilodyn和Resistograph检测方法均是活立木基本密度无损评估方法，建立基于两种方法的湿地松基本密度评估模型，对两种检测方法进行对比分析，为湿地松活立木基本密度估测和育种提供技术支撑。

以24年生84株湿地松活立木为材料，利用Pilodyn和Resistograph两种无损检测方法快速测定各单株的密度相关值，同时通过分析Resistograph数据，计算单株年轮宽度及密度相对值；采用生长锥钻取木芯，按体积法测量对应湿地松木材基本密度，分析该密度值与两种无损检测设备测定结果的相关性，建立基于两种无损检测的密度预测模型，并评估两种无损检测的优点和局限性。

Pilodyn值与湿地松木材基本密度呈显著负相关（R=-0.30，P<0.01)；Resistograph振幅与湿地松木材基本密度呈极显著正相关(R=0.50，P<0.001）。Pilodyn探针探测深度为20 mm左右，但与阻力测定值相关系数较大的活立木外侧木材深度达到50 mm左右（外侧10 a左右树龄部分），从树龄10 a的年轮部位到髓心部位木材密度值与阻力测定值相关性逐渐降低。Resistograph能穿透立木胸径部位，全部年轮振幅值与木材基本密度均呈显著正相关，其中树龄5~18 a相关系数为0.42~0.58（P< 0.001），其他各年份相关性均达到P< 0.05的显著水平。Resistograph能够评估年轮宽度及年轮内密度，Pilodyn不具备该功能。树龄8~20 a（除树龄12 a外）密度与年轮宽度为正相关，其余年份为负相关，表明Resistograph在剖析径向生长规律方面具有潜力。

Resistograph和Pilodyn检测方法均具有快速、无损的优点，均可用于间接评估湿地松活立木基本密度。Resistograph比Pilodyn检测更精确，与湿地松木材基本密度相关性更强，并且可以剖析径向年轮生长和基本密度的年度变化；Pilodyn则没有这个功能，但是Pilodyn在设备经济性及使用简易性上仍然具有优势。湿地松木材基本密度与生长性状的相关关系与树龄有关，不同生长期木材密度差异较大，早期密度相对较低。

The vrood basic density is an important improved character to determine the wood quality of pine plantation. Pilodyn and Resistograph are non-destructive assessment tools for basic density of living trees. Establishment of basic density assessment model of Pinus elliottii based on two methods and comparison of the advantages and disadvantages of the two methods can be beneficial for estimating the basic density of living trees in breeding programms of Pinus elliottii.

Eighty-four Pinus elliottii trees aged 24 years were measured at breast height using Pilodyn, Resistograph, and increment borer. Resistograph amplitudes (A_E), width of each ring (R_E), and P value were recorded by Resistograph and Pilodyn methods, respectively. Wood basic density (ρ) was determined by increment coring. Correlation analyses of Pilodyn P values, A_E, R_E and ρ were performed.

Pilodyn P values were significantly negatively correlated with ρ (R =-0.30, P < 0.01). A_E was positively correlated with ρ (R = 0.50, P < 0.001). The strength of the correlation of A_E and Pilodyn P values increased from the 24^th ring to the 10^th ring and then decreased from 10^th to the pitch, suggesting accurate estimation of ρ by Pilodyn measurements; however, prediction of wood density in trees with large diameters was poor. A_E was positively correlated with ρ in general and produced a significant positive correlation (P<0.001) with ρ in rings produced from between 5 and 18 years of age. The correlation of A_E and R_E as measured using the Resistograph was positive between the 8^th and the 20^th rings, apart from the 12^th ring; however, other coefficients of correlation of A_E and R_E were negative. No corresponding results were obtained using the Pilodyn.

The Resistograph and Pilodyn devices can be used to indirectly and non-destructively assess basic density of Pinus elliottii, and although the Resistograph is more accurate for estimating basic density of Pinus elliottii wood, the Pilodyn has advantages regarding ease of use. Basic density of Pinus elliottii is high in mature wood (older than 8 years) and is relatively low in young wood.